CashMan wrote:
Using cards for everything is dumb. It makes you more likely to spend money on junk that you don't need because it's easy. If you rely on cash, it makes you stop and think about whether you really need something before you buy it. Cash is much better for sticking to a budget.
I disagree. For me, using the card feels more like spending "real" money. Using cash doesn't increase my statements so I don't really feel like I'm losing anything besides some wallet weight.
I'm a big fan of spending everything on cards. If you're responsible and always pay your balance on time the rewards can be quite nice. Between three credit cards that I use I get 2-4% cash back on every single purchase. Why not take the free money?
To answer the OP's question, anywhere from $50-200 just in case of emergency, but sometimes even less. Also helps for tips in certain situations.