After a fairly long search for a "reputable" seller of the Verbatim 8x DVD+RW that wasn't charging $8 per disc, I came up with "PCUniverse.com".
$3.03 per disc in jewel case and lots of it in stock. Shipping is pretty high, but I still managed to get 6 discs for $30 all in.
I did find a few other cheap sellers, but this one has the best buyer ratings, and some of them have horrible ratings. You can order through Amazon, or directly.