Originally Posted by 10 Wheels
I think you are to heavy for a full suspension bike.
Look for used on Cragslist.
He is in no way too big for full suspension.
Although I would say, for casual riding and your price range, you won't get good suspension. Additionally, at 5-10 miles/week, you won't really be riding enough to appreciate the full suspension and I am guessing you won't be on trails that warrant full suspension.
Your best bet is Craigslist, if you know what you are doing. You can find way better bikes than you would be able to buy new in the price range your are talking about.
I would not have any suggestions of particular bikes in your price range except to say, avoid suspension if possible. You may not be able to find one without front suspension but don't expect much from it.
Taken care of, the chain store Xmart bike can last awhile. Don't spend alot fixing it up. Save your money for something better on the next go round.