I use paypal quite a bit, and generally - they do a good job. But with what you have in mind, be aware that there is a chance they may freeze your account if an unexpected high volume of payments come in - which is documented here:
http://en.wikipedia.org/wiki/PayPal#Criticism
I don't mean to put a downer on your plan, as it is extremely admirable, but something that you should be careful of if 'too much comes in too fast'.
- Paul