I'm personally not against those things scaling without necessarily getting more expensive (within reason), because I don't see a problem with it - most other Actions scale by level simply because you get better at the task, why would you not get better at, say, throwing an Alchemists' Fire so that you do 2d4 instead of 1d4, or whatever, without having to buy a bigger flask? (Maybe you should ALSO be able to buy a bigger flask at various tiers to keep up with scaling).
OTOH, I don't want to wind up with it all being a "MOAR DAMAGE" - race, either.
Yeah, that'll be the trick.