You may set up different payment processors depending on how you wish to accept payments from customers and shape your billing process. To take a decision which processor to use, we'd recommend the following:
1. Note that E-junkie supports:
Both Buy Now buttons and Shopping Carts with PayPal, Google Checkout, Authorize.Net. If you plan on selling tangible items you should consider using one of these processors to be able to benefit from the shipping, handling and tax calculator integrated with the shopping cart buttons. We'll review the setup of these processors in mode detail.