For $345 you should be able to get somethng decent off of eBay. A 2-5 year old Trek hardtail, or better, might be a good choice. Start at the number 4000 and work your way up (the higher the number the better the bike and components). You might even get up to a 6500 or 7000, which would be a great bike. If just for riding around then put a set of street tires on it in place of the knobbys.