I love Paypal and Ebay. One thing I would absolutely recommend to anyone is to take the time to read the Paypal TOS. There are timelines, reviews of what they protect and what they do not, and how to proceed if one has issues.
There isn't always smooth sailing, I've had issues buying bicycles on Ebay but none of the issues were connected to Ebay or Paypal.
On the other hand, what with the price of gas and all, I've made many purchases that I believe were less expensive than they would have been if I had tried to find the same item locally.