Back to Guilds, I noticed this text in the Dark Ages rules:
If you use Band of Misfits as a
Throne Room (from Dominion), King's Court (from Prosperity),
or Procession
To my knowledge there is currently no way to ever have KC cost less than BoM - the best you can do is make them both $0 - but this may be a small Guilds spoiler. It's not uncommon for rules to incorporate some info about future expansions. When you read the rules for the first time things sometimes don't seem to make sense. Rules may seem more complicated or confusing than need be, but as new expansions come out you can see why the original rules had to be formulated that way.
In this case we can imagine there might be a card in Guilds that looks like the following:
Discounter - Action - $4
+1 Buy
Name a card. While this is in play that card costs $3 less.
As Guilds deals with paying more for cards and might otherwise modify costs, I think this might be a good fit.
That's incredibly strong. On its own, it very easily allows double-$5 buys very early, and double-$4 buys even earlier. Take off the +buy and maybe it's more balanced.
I'd think something more like this:
Discounter - Action - $4+1 Card
+1 Action
+1 Buy
Put a Discount token on top of a Supply pile other than Discounter. Cards cost $1 less per Discount token on top of their Supply pile.
It doesn't provide much on its own (really just the first opportunity to buy the card you've discounted) but causes some crazy shifts to the game and provides interesting opportunities to end the game (e.g. discount a card to 0, immediately kill the pile). The one problem I see are kiloturn endings where one player discounts the Provinces to 0 or 1 and immediately kills the pile. I tried to mitigate that by disallowing players from spamming Discounter by immediately discounting the Discounters, but it still seems like Province discounting would be rampant, and I don't want to disallow Victory cards because that makes the card less interesting.
The other option is to include a drawback for buying discounted cards, but it's difficult to come up with one that's not either pointless or overkill. You obviously can't have it throw junk per discount token, since that would be too much (and cause Discounter to function as a slightly modified Embargo). You can't have it throw one regardless of # of discount tokens, since that would be too little and cause it to still function as an Embargo for the first discount. -VP is out of the question for the obvious reasons. Limiting buys of a discounted card also makes it less interesting. Having buys take discount tokens off the pile makes it too strong and less interesting.
Overall, the more I think about it, the more I see it as a terrible idea: it's awesome for kiloturn strategies and really isn't that useful otherwise, and I see that as a mark of a badly designed card. Thoughts?