PayPal is an electronic funds transfer service – a way of zapping money by email. Almost anyone can use it. All you need to know is the recipient’s email address. For affiliate merchants, PayPal puts an end to the old days of printing checks, stuffing envelopes, paying postage and waiting for checks to arrive. Once you’ve joined PayPal you can earn commissions by recommending PayPal to merchants. Recommended by Allan Gardyne, AssociatePrograms.com..