How do you manage to stay out of debt? Simple - don't buy stuff you haven't already saved up for. While this sound like something to be filed under the folder marked "Duh", it's amazing how many people don't follow it (hey - in an earlier life, I was one of them).
Here's a great Saturday Night Live skit by Steve Martin titled "Don't Buy Stuff You Cannot Afford" (it's on Salon.com - just click through the adds). Here's another version with no ads, but you have to have the Flash player installed.
I have to go teach my undergrads in a few minutes - I think I'll play it for them. It couldn't hurt, and it might actually do some good.
HT: Consumerism Commentary