This may sound weird, but I don't feel the need... yet. My conscience rules my spending. I'm frugal, if I do any spending that's not consistent with my philosophy, I'm 100% aware of it. Now, this might not be the wisest way to keep a leash on your spending, but it's worked for me. To give myself a longer leash I figure I need to increase my spending power, and for me that means growing my liquid assets. That project and my spending habits aren't really harmonious exactly.
Anyway, this thread has my attention, partly because I get these paper receipts in stores and very often something gnaws at me when I contemplate whether or not to toss them into the trash. "What if somebody tries to game me," or "what if they make some mistake in their processing of my purchase, will I catch it, will I need proof of the transaction?" is my thinking.
In any case, I'm anything but hounded by debts.