That's a good price. I say do it. Just really try to avoid potholes (sometimes easier said than done) and cut down on the curb jumping and/or learn how to take curbs w/o huge impact on the wheels. 28c is fine. Any bigger would suck.

If you notice problems with the wheels going out of true, sell them off and start looking for something with more spokes. It isn't that big of a deal.