ok, i can't really recommend it, because i haven't seen it yet, but i will venture out on a limb and say that wal-mart: the high cost of low price is probably going to be worth the time it takes to sit down and be utterly horrified at the machinations of the world's largest corporation (yeah, that's right, not merely the largest retailer, but the largest corporation).
there are plenty of sites detailing the ravages of wal-mart on the world. i won't bother to recap them here. have a look around and see what you can turn up for yourself. it'll be far better than anything that i could say anyway.
i will tell you that i have had the joyous experience of working for a supplier of wal-mart and will be happy to go through the rest of my life never repeating the experience. it's a very hard game to win. once you start down the slippery wal-mart slope, you are locked into a cycle of providing them with "more for the same or the same for less" every year. that means that every year you do business with them, you have to find a way to lower your price (whether by dropping the price or by including more at the same price). this is very tricky because, as most people know, prices have a tendency to go up, not down.
make yourself aware of what this corporate giant is doing. in the long run, you're not getting much value for your money.