AR Lower/Starter Parts?

[Goooh]

I've decided to do a build from scratch on an AR-10. I'm going to hit the gun show in Lafayette and/or Houston, and being that this is my first build I need to know what to look for and what a good price is for something decent...

Can I get something that will accept plentiful/cheap magazines?

Also recommendations on good starter parts that I might find there are welcome, is LPK something available at the shows? Trigger Guards? Grips?

Thanks for the help, and patience working with a newbie...