Mountain Biking - Mountain bike Newbie- FT Worth Tx, LBS?

I decided that I would like to get into mountain biking. I went by a local dicks today and just sat on a few bikes to get a general idea, but decided against making any purchases before I did research.

Basically going into this I know I feel more comfortable on 20" and 22" frames. ( I'm 6'1" ) but if I might feel more comfortable on something smaller, I'll have to wait and see at a Lbs, which is my problem.

I live in DFW, and would like to head to a LBS to probably make a purchase on a Used Hardtail in the 300 dollar range. Dicks had some DB Responses for around 300, but from what I read in the read first, generally since the ones there had disc brakes other parts are probably not as good?

Can anyone recommend me a LBS that I should head to where I wont get ripped off, or generally get a good deal?

I read the Read first, but to be honest I'm much more of a audio / visual learner. I don't retain what I read very well. I would rather speak to someone in person.

What part of DFW are you in? I have a favorite LBS (City Cyclist on McCart just south of I-20 in Fort Worth- see my sig link). I know the owners do a lot of rough trail riding and have a good experience level in that area. I would go in and talk to Debbie or Mike. Even if they don't sell a bike to you, they are very helpful in educating you so you know what you're looking for. They're bike enthusiasts there, but not hardcore performance cyclists, so they understand the entry level customer.

In north fort worth area... 35 and north of the 820 loop. NRH, Haltom, etc. But willing to drive anywhere to get info. ALso work in the south dallas area, so could always look at a place near or around where i work too.

If you want to take a ride south, you can get to my LBS by taking I35W south to 20, then go east a couple exits to McCart and turn south (left). They're on the right, across the street from the Starbucks, right after Walgreens.

The other place I know where some people buy their bikes is Bicycles Inc. which has several locations including one in the HEB area which is probably closer to home, and along your commute. I've heard mixed reviews about how well they listen and explain things though. They are local, but a pretty big chain. So you're not so much talking to the owner, you're just talking to someone who works there, so there is a little more variation on each person's knowledge base.