I think these CDRs are STI brand 650 MB. They were identified using CDRIdentifier to be made by Princo. I have heard that Princo is one of the worst CDR manufacturers. Well, they are "free," so get them if you want some really cheap CDRs.
By the way, not all CDRs sold at B & M stores are good. The "GQ" brand CDRs sold at Fry's were pretty crappy. They are labeled as 12X but they don't work even at 8X. Okay, maybe others are okay, but the GQs are the worst.