I'm somewhat wary of buying anything more then raw materials at walmart. Especially well regarded brand names - a lot of times they will have special product lines just for walmart that are made to lower quality standards and use inferior parts/materials. I know it's the only place to get some items in a lot of the U.S., and I'm rather lucky that I live in an area where I have other options, and would have to go to some effort to get to a walmart.
I thought the book "The Wal-Mart Effect: How the World's Most Powrful Company Really Works-- and How It's Transforming the American Economy" by Charles Fishman
was pretty interesting, without actually demonizing the corporation.
Anyways, as to timers, I've always been partial to those ones with individual blocks that are pushed up/down. It gives the option of multiple photoperiods, and is pretty easy to use. I just keep an eye on them, check them every week or month or so, and occasionally re-adjust them. pretty reliable and low maintenance, in my experience.