I think it's fine to use cheap panniers for commuting. My grocery bike/bad weather commuter has a pair of Nashbar ATB panniers I paid less than twenty bucks for. They're black nylon and have plenty of pockets and expandability. I've used them for several years and they're holding up fine. Plus, if somebody jacks them while the bike is parked, I'm not out a bunch of money.That being said, my Carradice Kendal panniers will likely last a lifetime, and I have the satisfaction of knowing they were handmade by some nice English lady. :-)