The cost of a card or Event is the amount that must be paid in order to buy it. A card's cost is indicated in its lower left corner, and an Event's cost is indicated in its upper left corner. Every card and Event costs some number of , , and . Only relevant cost components are shown, the rest are omitted. If something does not cost any resources (besides a Buy), is shown. To buy something, a player must have the requisite number of and unspent, a Buy, and no .
 Symbols in costs
Most cards include Coins in their cost, symbolized . To buy a card with in the cost, you must have made enough during your turn. The primary way of making is by playing Action and Treasure cards. Coin tokens and some Events, Boons, and Night cards provide additional ways to make .
Some cards in Alchemy include Potion in their cost, symbolized . This may be in addition to some number of . The and components of costs are orthogonal; is not greater than, less than, or equal to . To buy a card with in the cost, you must have played a Potion, in addition to having made enough to pay for the portion of the card's cost.
Some cards in Empires include Debt in their cost, symbolized . This may be in addition to some number of . The and components of costs are orthogonal; is not greater than, less than, or equal to . Unlike and , players do not pay when buying cards costing ; instead they take tokens when buying cards costing . is paid off by .
Some cards include an asterisk in their cost (e.g., non-Supply piles have asterisks in their costs to remind players that, despite having a cost, they cannot be bought. Peddler has an asterisk in its cost to remind players it has an effect which changes its cost. Cards with asterisks are in Prosperity, Cornucopia, Dark Ages, Adventures, and Nocturne.). This indicates there is something unusual about the card's cost. Cards from
Asterisks and plus signs are only reminders; unless otherwise specified, a card still has its normal cost for all purposes described below.
 Comparing costs
Many effects cause players to compare the cost of a card to another card, or a fixed value. These commonly include effects from gainers, remodelers, and trashing attacks. An amount of two cost components ( and , or and ) is only larger than another if both cost component amounts are larger, or one is larger and one the same.
- costs more than .
- Any card with or in its cost does not cost up to .
- Any card with or in its cost does not cost from to .
- costs more than , but does not.
- is not more than , and is not more than ; both have something the other lacks.
- Things that change costs only change the cost; and are unaffected by changes in .
 Purposes of costs
The primary purpose of a card's cost is to indicate the resources needed to buy it. However, many things make references to a card's cost at other times. For example:
- Most gainers and several trashing attacks can only gain or trash cards with specified costs.
- Most trash-for-benefit cards have effects that depend on the cost of the trashed card.
- Only cards with certain costs may be Young Witch's bane.
- Only cards with certain costs may be imitated by Band of Misfits or Overlord, or be set aside by Prince, Inheritance, or Summon.
 Changes in cost
Some things have effects that temporarily reduce the cost of some or all cards: Bridge, Bridge Troll, Highway, Peddler, Princess, Quarry, and Ferry. When these effects occur, the effected costs are changed for all purposes (see above). These abilities change the costs of cards, but not of Events.
In general, more "powerful" cards and Events have higher costs, but overall power is not the only consideration that goes into determining cost. For example:
- Chapel is often cited as a card whose strength is considered disproportionate to its low cost of .
- Costs between opening, and how desirable or necessary it is to be able to accumulate multiple copies of a card with extra Buys. and are influenced by how useful the card or Event is as an
- Cards with beneficial on-gain or on-buy effects typically cost more than their on-play effect would seem to require.
- Some cards' costs differ from what their power levels might suggest in order to interact better with other cards. Rats costs to interact favorably with trash-for-benefit cards, while Border Village costs to give you a wider range of other cards to gain with its when-gain ability.
- Until Adventures, non-Supply cards exclusively cost regardless of their effect, but since that set, they generally have a cost indicative of their overall power level.
In general, a card will never be strictly better than a similar card with the same or a higher cost.
Most Kingdom cards cost between and . There are only eight Kingdom piles with cards costing more than (as well as three Events) and one Kingdom card costing less than (as well as five Events). (Note other Kingdom cards and Events cost , but do cost or .) This means most games of Dominion do not have Supply cards costing or . These gaps can influence gameplay in subtle but substantial ways. For examples, Upgrade can trash Copper without gaining anything, and cannot trash anything to gain a Province. In the rare games when cards costing or are in the Supply, the utility of a card like Upgrade can change dramatically.
 0 cost
Cards that cost Copper, Curse, and Ruins), or are non-Supply cards that are meant to be quite powerful. In the latter case, a null cost helps indicate that these are not normal cards, and discourages any other use for them than playing them (such as remodeling them).are either meant to be so terrible that they're essentially free (e.g.,
Events that costare meant to be always available, and come with some penalty or restriction to prevent their abuse.
 1 cost
Cards that cost Poor House has this cost for flavor reasons, and to change early game playstyles.do so mainly as a gimmick:
Save, the only Event that costs , has a relatively minor effect that is intended to be almost always available.
 2 cost
is the lowest normal cost for Kingdom cards. Cards that cost are priced so players can always open with them, and can easily pick up extra copies of them with spare Buys. These include:
- Cards whose effects are usually relatively weak or inconsequential (e.g., Pearl Diver and Duchess).
- Cards that are strong only in multiples (e.g., Fool's Gold and Native Village). These cards are valuable because they are cheap enough you can buy several of them.
- Cards that are not strong in multiples (e.g., Courtyard or Hamlet). These cards are not overpowering because, although you can buy several, they have diminishing returns; it is usually not useful to buy too many copies of them. Chapel epitomizes this: it's often described as the strongest card in the game relative to its cost, but rarely does anyone need more than one copy of it.
TheEvents mostly give +Buy and a small but useful bonus, offering another use for extra the player may have in their Buy phase.
 3 cost
Cards and Events that cost Silver.are priced so that players can open with two of them, but cannot (usually) open with one of them and a card costing . They are typically more powerful than cards and Events. Cards and Events at this cost also directly compete with
 4 cost
 5 cost
 6 cost
Cards and Events that cost Gold. They tend to be exceptionally powerful, and players usually cannot open with them.directly compete with
 7 cost
Cards and Events that cost remodelers that gain cards costing "exactly more than" a trashed card to gain Provinces.still compete with Gold, but the extra in cost means these few cards and Events are just that much harder to acquire. Cards costing can be seen as a consolation prizes for not making , but they also allow
 8 cost
Cards and Events that cost Province; a player chooses to buy these cards and Events instead of a Province. Peddler, while nominally costing , is rarely purchased for more than . By coincidence, until the release of Empires, all cards and Events that cost had English names starting with the letter "P".directly compete with
 9 and higher cost
Platinum at and Colony at have the most expensive costs of card piles in the game, and Dominate at is the most expensive Event in the game. The two most expensive Castles also fall into this price range, and all the cards and Events in this category can be extremely powerful. Games with these high-costing cards usually last longer as players build their decks up to make enough to buy them.
 Potion cost
Since the only way to buy a card with Potion card, such cards are generally more inconvenient to acquire than comparable cards with costs. To motivate players to go to the trouble, these cards are typically powerful and reward accumulating multiple copies of them.in the cost is the relatively inflexible
 Debt cost
Debt allows players to pay some or all of a card or Event's cost at a later time. Cards and Events with solely in their cost can be bought at any time, provided the player does not already have . Thus, while they may be expensive, they can be bought on a player's opening turns, though this may mean that they can't buy anything else for the next turn or turns. As such, cards and Events with no other cost tend to have some feature or penalty that makes them not worth buying in the first few turns.
One card (Fortune) and one Event (Wedding) have both a cost and a cost; the same concepts from the purely -costing cards and Events apply, but now these two have an additional threshold that must be met as well, rather than being able to buy them at any time. At , Fortune is the most expensive thing in the game, though since only half of that cost has to be paid up front, it is easier to access than Platinum, Colony, and Dominate.