http://www.aimsurplus.com/product.aspx?item=XTSTRXAL111BT01&name=Troy+Ind.+11%22+Alpha+Battle+Rail+Black&groupid=591
About half your budget and easy to install on your existing barrel nut. They do make different lengths if you don't want to put on a low profile gas block.
I have never seen a sign at them but apparently corporate says carry is a no go.
http://www.bayoushooter.com/forums/showthread.php?75478-AMC-Theaters-No-weapons-policy-response-from-corporate&highlight=AMC
I actually just got back from the AMC theater near my house. Not one sign posted. A friend of mine that goes there more often than I do said hes never seen one either and he carries everyday.
I have the semi-compact in 9 and so far its been great. Shot it in the magpul handgun 2 class with no problems and I'm just now consistently having problems with it (worn extractor) after almost 10k or so down the pipe.
"The verbal equivalent of a shrug of the shoulders." -quoth me
"(While holding gun to their own head) Give me one good reason why I shouldn't pull this trigger!"
"meh."
Great example.
I went on a handgun kick when I hit 21. I think I had enough cash to buy one every month for a few months. Of course i was single and my rent was alot cheaper than it is now.