"Peel and stick" works very well. Lightweight. Good padding. Per piece cost is higher than I'd like. DVDs have not been damaged in the mail. I would not put more than 2 DVDs in thin cases into one envelope. Larger packs containing more than 12 envelopes at a lower cost per envelope should be offered.
I use lots of padded mailing envelopes for mailing out CDs. These envelopes are well-sized for the purpose but I would have preferred to be able to buy more than only a dozen at a time.