I was thinking about setting up Paypal. One issue I have is tracking. If I accept money today and want to refund it a year or two from now, do I have the proper tracking to know who sent me $$ and how much?
Paypal provides you with pretty much all the details from their history tab. You can go search on specific dates
Clicking on details will give you the full details
Within the date-range you can drilldown to specific events