Mountain Bike Protective Gear What Is A Good, Solid Mountain Bike For Not Too Much Money?

What is a good, solid mountain bike for not too much money? - mountain bike protective gear

My family started mountain biking in parks and other places, and I realized that my old machine a bit smaller. I need men's mountain bike with full suspension in the size and (preferably), disc brakes. I would spend about $ 300.00, but whether it's worth, I can not spend more.
The prospect of a mountain bike at this price will be very useful.
Thanks
I also have a cool bike Kawasaki, but I'm not a good thing.