Well, I’ve never been a big fan of buying a wal-mart (or similar department store) bike under any circumstances, but here’s an awesome article in Dirt Rag magazine about why you shouldn’t.
Deals on Wheels: How the Masses Do It. Basically what they found is that your average $150 bike from X-mart is a worthless piece of trash. Improperly assembled and barely able to handle forces equivalent to dropping off a curb, there’s no reason you should pay $150 for a wal-mart bike when you can buy a good beginner bike from a reputable bike shop for $250 (or less). Think about this as well… if you buy a wal-mart bike, every servicing, tune-up, and whatnot are going to cost you money unless you’re good enough to do it yourself. Your average full-blown tune-up at a bike shop is $50. Take your $150 department store bike and add a $50 tune-up once a year (you should do it more often than that) and you’re already at $200 after the first year. The bike shop I bought my bike from and many other bike shops give a year of free tune-ups. Figure one a month, or 6 a year if you don’t ride much. That’s $300 worth of tune-ups to go along with your $250 bike. Pretty good deal in my book. Think about the service, too. A bike shop is going to make sure you get a bike that fits you both physically and financially. Department store bikes are one size fits all. Fine if you’re 5′7, not so fine if you’re 6′1. It’s no wonder so few people really understand the joys of cycling. I’d fucking hate it too if I had a bike I bought from Wal-mart that kept fucking up every 3rd time I rode it and didn’t fit me properly.