There are many sellers on eBay selling ritek and princo dvd-rs for a pretty good price. But just cause the seller says they are ritek or princo, how can you actually tell whether they really are ritek or princo? Are princo the only ones with white-top dvd-rs? And what about ritek?

Well before you buy them I guess there is no way to tell.

Once you get them you can easily tell by looking at the disc or by using something like DVD Identifier as discussed in the sticky above.

There are white-top Riteks as well (Ink Jet printables). The only way you can tell 100% is by having them use the program mentioned above. The easiest way is to have them flip over the disc and tell you what color the dye is. Light Purple=Princo, Dark Purple=Ritek. Also I would definitely recommend not purchasing discs on ebay. 1. In almost every instance I can get them cheaper from reliable online sites 2. When you order from these sites you don't have this kind of dilemma (is it Ritek or is it Princo) 3. Most of them are auctions so you never know when you are going to be outbid at the last minute or some crazy bidder is going to jack up the price. 4. A number of sellers there either will confuse Princo and Ritek (hence your current dilemma). 5. If you get a good deal this time around there is no garauntee that it will be there for you next time. I have checked on ebay but I haven't found any closing prices or Buy it Now's that can beat the following prices: www.newegg.com 50 pack of G03 Riteks (1x/2x depending on your burner) for $43 with free Fedex ground shipping. Or you can find a 50 pack of the G04 (4x) Riteks for $55 with free fedex shipping. www.rima.com 25 pack of G03 Riteks for $25+shipping. 100 pack of the G03 Riteks for $82+shipping. 25 pack of G04 Riteks for $30+shipping. 100 pack of the G04 for $108+shipping. Newegg probably has the best reputation of any site on the net and Rima has provided reliable service to a number of us here and elsewhere (including myself). Don't get me wrong ebay is a good place for a number of things, just not DVD-R media.