iPhone app covers your coffee cost

Need a coffee but low on change? There’s an app for that.

Think of it as a scaled-up version of “take a penny, leave a penny.” But in this case it’s “get a coffee, give a coffee.”

Developer Jonathan Stark has created an iPhone app that displays the barcode of a Starbucks card, and allows anyone to use it and/or recharge it.

Simply have the barista scan the screen, and if there’s a sufficient balance in the account, it will cover your coffee.

All Stark asks is that if you use the app to pay for a cup, add a few bucks for the next person in line.

You can even follow the account’s balance on Twitter at @jonathanscard.