CompUSA has Memorex DVD-R media on sale this week (5/19-5/25) for $3.99 per disk, $2.00 off their regular price. This is the same price as CompUSA's store-brand media. I've used both Memorex and CompUSA media in my DMR-E20 with 100% success, so far. The CompUSA-brand media can be bought for even less if you buy them in 5- or 10-packs; the 5-pack is $18.00 and the 10-pack is (I think) $35.00. CompUSA also sells their store-brand of DVD-RAM for $6.00; these seem to be their regular prices, not sale prices (except for the Memorex). I realize that these prices aren't in the sub-$1.50 range like the Meritline disks and others, but like others here, I've had reliability problems with some of these brands.
Pelagic
Pelagic