The music dvds I own, and as such feel confident recommending are as follows:
Gwar - Ultimate Video Gwarchive, has commentary from the band on all the videos, which I haven't seen that much on music video dvds.
Weird Al - I can't remember the proper name offhand, but it's all of his videos. Worth it for Fat and Amish Paradise alone, I think.
Prince - The Hits Collection, some people complain about some of the omissions on this, but for what it is, it's fine, and with your discount it should only run you 7 or 8 bucks. And besides, the things left out are often available elsewhere, such as-
Prince - Sign O' Times, as far as I know only available as a Brazillian import, so it's worth having as a rarity. The video and audio quality dip in couple places, but nothing too bad.
Prince - Rave Un2 the Year 2000, the ppv concert from the turn of the millenium. A really really great concert, with appearances from George Clinton, Sly and the Family Stone and others. Super cool, I recommend this higher than anything else.