Your help please:

Gonna buy my first AR-15 at a gun show tomorrow. I feel like a high school kid about to get laid for the first time: I'm excited and horny, but I have an irrational fear that I'll do something wrong.  

I want to get a stripped lower and build it up myself.  Can't afford a pre-ban right now, so it'll have to be post.  Last show I went to the only lowers I saw were olympic arms, but this show will be much bigger.  Idealy I want a Bushy, but I guess I'll have to take what I can get.  

Are there any things I should be on the look-out for?  Any scams?  Any brand I should avoid?

Thanks!

Pretty Please?

Stick with the name brands and you will be fine.

SRM

Ditto with brand names. Still though, there is never a guarantee that it won't be defective but the chances are substantially reduced. You might consider getting the lower through your local FFL dealer. By giving them the business, they are more inclined to help you and give advice with building your first, or making good on a defective lower.
 When your done putting it together, make sure you get the headspace checked before firing it or you might just end up where you started, with an AR in pieces or worse. Then again this info may be all too familiar to you. Have fun in Phoenix I presume.

I have an Oly lower and an Oly kit. I like it just fine. One bit of advice. If you get the set screw muzzle brake, take it off and throw it in your spare parts box. Mine kept coming loose and became a hazzard. It shoots just fine without it. Have fun and bee safe!

Olympic Arms makes a damn good lower.  Quite a few people choose them because they are the least expensive receivers out there.  Least expensive doesn't always mean least quality either.  In this case it definetly is not cheap quality.  For a starter or first good the Olympic lower is ideal.  I've seen them at gun shows for $100-$125.  Bushmaster in my opinion would be a short step up both in quality and price.  The only caution I can give is stay away from the Hesse receivers.  On the Olympics the current receivers without the "Lowenbrau" lion insignia are cast receivers and the one with it on them are the forged.  The forged receiver is more prized than the cast.  In practice there really is no difference.  Some people just prefer knowing that their receiver was cut from a solid block of metal (forged) rather than having the two halves welded together (cast).