I've bought a few things on eBay and being careful, my experiences have been very positive. I find the sellers very happy to answer pre-purchase questions about their merchandise because many times the worded description isn't quite clear enough.

For example, when looking at the purchase of a Scarlet Macaw resin parrot ceiling hanging decoration. The description may say 27" bird. However, upon questioning for specific measurements, learned that was from the top ring of the perch to the tip of the tail. In actuality, the "bird" was only 12". Makes a big difference especially when comparing products with other sellers.

PayPal is a lifesaver as already mentioned. Be very attentive to reviews of the seller and if they have that special top seller designation thingy from eBay.

Bottom line, if one pays attention and ask whatever questions come to mind, you will have a very positive experience. The insights given in previous posts have been excellent.