I told my girlfriend, who is a lawyer, about Bullseye and she had two things to offer:
1) In response to the poster above who joked "libel and slander be damned!", she pointed out that it's only libel or slander if what you're saying isn't true. As long as you're being factual, you have every right to badmouth Bullseye.
2) She was very interested in the "Mini Strategy Guides" he's selling. If they are in fact printed up from a website somewhere, his selling them for cash is illegal. She suggested someone buy one of the guides, figure out what site it's from, and alert that site that their content is being sold by Ryan on eBay.