United States proof sets

I have several mint condition proof sets.
Where is a category for this?

Hi - sorry to say we don't have a category for Proof Sets, since there is no way to tie a single grade to all coins in the set. We don't have a good way for them to fit our pricing model - (single grade to single coin). You could always just mention that you have them available via your store and to have people contact you if interested.