As others have stated, for 250$ you'll be getting a bad bike, short-life, bad components which will break. You know what happened with my 180 euro bike (=250$?)?
After 9 months the suspension is broken, the gears are messed up, the crankset is bent, the wheels are a bit bent, the brakes suck and all this with relatively light riding.
Trust me: Either get a 500$ mountain bike used or save up some more money. (when I get enough money I'll be getting the Specialized Hardrock Sport, great bike, 425 euros but I think in the USA it's around 400$, maybe you should check it out and see if you can find a used one on eBay)