1. The way changes to consumer surplus are discussed with respect to a price ceiling in intro classes. When you have a price ceiling, anyone wiling to pay at the level of the price ceiling can be in the market. You can't just assume that the people to the left of the point where the price ceiling intersects the supply curve are the ones who get the good. It's quite possible that those with lower reservation prices will get it. So the consumer surplus gains associated with price ceilings are almost certainly overstated. It's true that if you have a higher reservation price, you'll probably exert more (non-price) effort towards getting the product. But to the extent that is true, the actual cost expended to get the project will begin to approach the market price. This is basically the discussion of scalping.
2. I hate the argument by retailers that you have to make a minimum purchase with a credit card because there's a fee for each credit card transaction. The argument is bullshit. It would be trivial to spread that fee cost by raising the retail mark-up. This is no obstacle whatsoever for them. That's not the reason they have minimum credit card purchases. The reason why they have these minimums is to get the guy that doesn't have cash to frantically purchase three bucks worth of extra stuff to meet the minimum requirement. They know enough people are going to do this, rather than leave the store without a purchase. Push back on this - they can run your credit card, after all. Say "but the cashier I had the other day let me run it" or complain about how prominently they post the minimum requirement.