What brand are they?
I'd suggest being very careful when purchasing off-brand discs (even some brand names aren't that great)...they usually are not as high of quality and its not uncommon to have 20 or 25 bad discs from a spindle of 50. In the long run you usually don't save any money...yea, you might have paid half as much for them...but half of the discs you got were useless. Add in the time wasted (not to mention headaches, medicinal costs, lost sleep, stress, etc.) and its just not worth it. Most, if not all, of those no-name brands consist of the discs from batches rejected by the name brands (there is only a few actual manufacturers that every "brand" buys from).
Memorex Printables (currently the same price as the non-printable ones @ CompUSA [DVD-Rs]) have always given me good results. I've also had good luck with Verbatim, Imation and TDK media.