The topic question is what I hear too often when trying to buy something while travelling abroad. So I have only big notes for a purchase of minimal price. What I pay with cash is drinks, snacks, small meals, bus rides, tips or other minor payments. Bigger payments like flights and hotel nights are usually paid by credit cards. Paying with large notes also eats my credibility as a budget traveller. Imagine, for instance, haggling hard for a cheap taxi ride only to hand over a large note hoping he got enough change.