For instance, Apple offers customers up to 18 months interest-free on purchases on a card from Barclaycard US. But if you don't pay off that specific purchase in the interest-free period, you'll face a variable annual percentage rate that's currently about 23%, according to the Apple website.
Others - like Wolfgang Munchau in Monday's FT - are sticking with the view that Greece is better off getting to a primary surplus before defaulting, so it wouldn't face an Argentina-style bout of further austerity as a result of losing access to international markets.