Cost reduction
Cost reduction is a recurring mechanic in Dominion. Rather than directly fielding coin, cost-reducers decrease the cost of cards, an effect which becomes more valuable with more buys or gainers. Typical cost reduction instructions follow this wording:
- [All cards or some subset of cards] (including cards in players' hands) cost
less this turn.
A general rule prevents costs from going below 
. Prior to the 2019 errata, the stipulation "but not less than " was included in the card text of cost reducers themselves, rather than in the general rules, and that clause was never included in any of the cards of this category in Menagerie.
Reducing a cost in 
does not reduce a cost in 
or 
. Reducing the cost of cards does not affect the cost of Events or Projects.
Contents |
List of cost-reducers
- Bridge - the archetypal cost-reducer
- Quarry - reduces Action cards by
- Princess - reduces costs by , but only one copy
- Highway - cantrip
- Bridge Troll - durational cost-reducer
- Ferry - reduces a single Supply pile's cost by
- Inventor - gains a card costing up to
before its cost reduction kicks in
- Canal - reduces costs on your turn for the rest of the game
List of cards that can reduce their own cost
There are currently four cards whose cost is variable. These have a base cost which can be changed by something that happens during your turn. Of these, three are in the Menagerie expansion
- Peddler - cost is reduced by per Action card in play, but only during your buy phase
- Destrier - cost is reduced by the number of cards you gained on that same turn
- Fisherman - cost is reduced by
if you have no cards in your discard pile
- Wayfarer - cost is equal to the cost of the last-gained card, and can even become more expensive than its base price
Animal Fair, also from Menagerie, is an odd case: it can be bought for if you trash an Action card from your hand, but its numerical cost doesn't change as part of this effect.
Strategy
Most cards that reference a specific cost in do well with cost-reducers, as most such cards use the specific cost as an upper limit. For example, Workshop can gain any card costing up to ; without cost reduction, this effect is rather weak, but with four Highways in play, a Workshop can gain Provinces. On the other hand, cards that give a scaling effect per cost in of another card (most often trash for benefit cards) will do less well with cost-reducers, as their effect will be diminished, and cards that reference a cheaper card will give no effect if their cost has been reduced to . For examples, trashing a Silver to an Apprentice when you have Princess in play will only draw you one card, and with five Highways in play, Band of Misfits can't do anything.
Since cost reduction affects cards but not Events, it is less useful for strategies that depend heavily on buying Events (or Projects).
Trivia
Cards that increase costs
Some of the issues - stacking, timing vs. cost reduction - can be solved, but the solutions take words, and you end up with something too complex. There's no special beauty to doing it that has pushed it into existence despite that.
Punishing buys is okay and there's some of that, e.g. Embargo. Contraband and Delusion try out limiting buys. And Peddler gives you the positive side, where a card costs more for your Remodels.
