If you sell physical goods somewhere like a market, it's hard to accept credit card payments unless you get specialist hardware from your bank. PayPal is now offering a card reader to attach to an iPhone or Android device, which works in conjunction with the PayPal Here app to process payments on the spot.
Right now, PayPal is only letting a selected group of merchants use the iPhone app. General availability is slated for "the near future", which is not helpful. However, PayPal has said that any business which registers its interest on its site in the first six months (that is, between now and mid-September) will get the swipe reader for free.
The catch? You'll have to pay PayPal fees, which are $0.30 plus 2.4 per cent of the transaction value (which rises to 2.9 per cent if you have to enter the card details manually). You might be able to score cheaper merchant rates from your bank.