Yeah, dude, I can't believe no one answered your question in 10 WHOLE MINUTES! Especially when all they had to do was copy and paste from the "Please Read Before asking Questions" FAQ that's stickied on the top of this page. What a *****ty forum. Must be populated by a bunch of jerks.
Oh, here's the relevant part of the FAQ that you were supposed to read before posting. The relevant part is the first couple sentences of the post, by the way, so you wouldn't have even had to search:
Originally Posted by Dannihilator
Part One-Recreational
So you are looking for a bike for recreational duties and/or your toughest trail is a paved trail. A mountain bike may not be needed in this instance, but if you plan on eventually trying out here are some things to take note of.
1-You don't need a top level mountain bike, you will need something more simpler. First step, avoid full suspension at all costs. A hybrid may be more your needs, but if you want a mountain bike get a hardtail for your needs.
2- Now unless the bike is used, the fork on it will be nothing amazing, so don't think that you will be getting something amazing like a Manitou Sherman, Marzocchi Z1 or RockShox Sid or Pike. For your price range you will see a bunch of offerings with low end Manitou, low end rock shox, RST, SR Suntour, and N'sync. They are basic forks for non aggressive trails, perfect for a beginner.
3-Other than the fork the parts spec will be low end shimano or sram or in house parts. Again the level could be higher on a used bike, but those parts could be somewhat worn.
4-The geometry on the bike will be more of a relaxed stance, for a bike in this category you don't want a bike with a dirt jump geometry.
5-The tires will be of a xc level.
6-What is high end for a bmx bike price wise is low end for a mountain bike.