oh hey, someone finally responded! haha
Square doesn't really work for us, because we're all cash, credit cards are an extra fee/take too long/more hassle/take your pick. We may tack it on at some point, but it just eats into our profits, and we have very few people who want to pay with a card, then walk away when they can't.
Notebook doesn't work either because the whole point of the registers from the fair's standpoint is to have a list of what we sold, so they make sure we're paying the correct percentage to them, not skimming off the top. Obviously it's pretty easy to cheat the system with a register as well, but that's how they want it.