If you've got a broadband dongle, or your smart phone can provide a portable wifi hotspot, or even if you can access a BTFon site via a laptop/ipad, smart phone Etc., you can have customers pay via paypal from a craft event. The problem is convincing the uninitiated that your phone/ipad/laptop will not store the data.
For the "part-time" seller it's worth noting that there's a ceiling at which paypal notify HMRC of your "takings".