Comment by zzo38computer

I think that a better way (which is protocol-independent, and does not require a web browser, or even necessarily an internet connection), would be a kind of payment specification which is placed inside of a order file. This payment specification is encrypted and digitally signed and can be processed by the bank or credit card company or whatever is appropriate; it includes the sender and recipient, as well as the amount of money to be transferred (so that they cannot steal additional money), and possibly a hash of the order form. A payment may also be made by payphones or by prepaid phone cards (even if you do not have a bank account nor a credit card), in which case you may be given a temporary single-use key which can be used with this payment specification data; if you do not do this, then you can use the credit card instead.