eBay: Advice for Buyers

How to determine if an eBay seller is any good.

If the seller has more than just a few negative feedbacks, you should not bid. This is true even if the seller has sold thousands of items. You may say to yourself, "20 negative feedbacks isn't that bad for someone who has sold 2,000 items – that's only 1%". But 20 negative feedbacks is a terrible track record. It is entirely possible for a seller to sell thousands of items and get very little negative feedback. Do you really want to buy from someone who has made 20 customers angry?
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You should also look at the seller's responses to the negative feedback. If the responses are angry and defensive, then you should avoid that seller. In addition, you should look at the feedback the seller has left others. If the seller gives a lot of negative feedback, then you should avoid that seller, as it means you may get negative feedback too.
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Some sellers have discovered a dirty little secret, and that is that they can get negative feedback and still do a good business on eBay. They have learned that there are plenty of careless buyers who don't check feedback or don't know how much negative feedback is too much.

Given my (meager) experience on eBay, it seems that an approval rating of 99% isn't all that good, and 98% is scraping rock bottom. Hell, Paypal won't let sellers provide Buyer Protection if the seller doesn't have at least a 98% rating. That fact in itself says volumes.