Here are some links

• Nice PayPal Button Lite
  • I would upgrade to Nice PayPal Button for $15US (it says $19) you get MANY more options like your own image instead of buy now, you can add text to the boxes before you get to Paypal etc.
  • see docs for Lite and options available vs. the docs for the full thing.
• WordPress Easy Paypal Payment or Donation Accept Plugin –
  • up and running in seconds
  • you have to put your paypal email address in the box – which is not great
• Quick Paypal Payments
• FoxyCart Plug in – had an error when I added a product – so I never tested it not even a little. Sad because it had a 4.5/5 rating