I've biked some of the best trails in the world, such as the Slickrock bike trail in Moab and trails all through the Colorado Rockies. I bought my bike and my wife's bike at a police auction. I have a full suspension 2007 Gary Fisher Cake 3 that I paid $200 for and the wife has a hardtail Specialized Hard Rock that we paid $110 for. Both bikes have had many upgrades to them since I bought them, but even my bike has no more than $400 total invested in it, for a bike that is comparable to a new $2000 bike. So, if you look around, it is possible to get a real mountain bike for cheap. The department store bikes have no real frame geometry which means it will destroy your joints and break itself apart in no time. Trust me, I used to have a Next myself. A Next won't even fit into a standard bike carrier because the front axle is too small. The lowest gear on my old Next is equivalent to approximately fifth on my Gary Fisher, making steep hill climbs nearly impossible on the Next. If you want a full suspension bike, the center shock should be an air shock with rebound control, if it's just a coil spring it will cause more harm than good. If getting a true full suspension bike is out of the question, just get a cheap used hardtail like a hardrock or rockhopper and upgrade parts on it down the road if you want to. You won't believe the difference. Also realize that if you're buying a real mountain bike, you'll want to make sure you're getting the correct frame size. The manufacturers usually have frame sizing charts on their web sites that take into account, height, weight, and gender. Frame size is usually measured from the bottom of the pedal stroke to the top of the seat post mount, or many bikes have the frame size printed on them, such as 15, 17, etc... As for upgrades, nashbar.com is the king. Great quality stuff for super cheap.
