Need a battery and someone to help me install it. (Around DFW area)

I was at a comp a week or so ago and some of the guys told me about a store called Mr. Battery where I could get a good battery for like $70. I googled this place and couldn't find it though, so I don't even know if it exists. But if it does, if someone could tell me where the hell it is that'd be awesome lol.

Also, since stores always charge ridiculous installation prices, could anyone help me install it for free? I'm sure it's not hard, but I'm remarkably dense when it comes to this ****.