Spent some time hanging out at a Performance Bike shop today while waiting to meet some one. Having nothing better to do, I spent a lot of time looking at bikes......
I wandered across a GT Zuma 5 MTB/Commuter. It's rigid fork, has a Shimano drive train, and was less than $300. Wheels may be a concern depending on planned use or current weight but it looked like a nice well built bike.
2009 Cannondale Caad9-7/2009 BMC SLX01/2011 Marin Nail Trail 29er
I have a $300.00 dollar GT right now that i ride. I use it when i ride with my wife and when i ride to work. I put slicks on it and have had no problems. The frame is made like a tank, and the rims are as well. I bought a pannier for it but have not installed it.