...the cards I'm trying to buy literally have a "Best Offer" listed. So I match that every time. They decided on the price, so I met it.
I think I might have figured out your problem,
@abworkout. The "Best Offer" is NOT a price set by the seller, as if they're revealing their lowest accebtable price. What you are seeing is the "Best Offer" that some other buyer has offered to that seller (which they have not chosen to accept, so far). If you want to become the new "Best Offer", you need to offer a price that is higher than the current "Best". The seller may still ignore your offer, but it should improve their likelihood of seeing your offer.