If it seems too good to be true, then it probably is!
I would steer from many of the Internet sites that offer all region DVDs (to include many eBay sellers from China). Buying from a reputable/legal retailer or from private collections is the best way to ensure you get good, high-quality and legal discs. Some others will sell you what might be a pirated disc. I looked all over this listed site and cannot find any info on a return policy or clear contact information (usually a good indicator of pirated discs). Remember, not all countries share our views on copyrighted material and are allowed to openly sell whatever they want. I would be cautious.