I use my AR for just cassual shooting on the range with the kids.  We would like to put an inexpensive scope on it (It has a carry handle).  I only paid a little over 500 for the gun so I do not want to spend alot on a scope.  Max range will be about 100 yrds.  Are the Ebay scoped any good?  Like this one:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3615988601&category=31714  
or
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3614737100&category=7307

Or even better:
http://www.thehuntersmall.com/noname7.html

I had a NcStar Scope on a budget Mauser .308, a 3-9X one. I was surprised at the lens quality...not a bad scope really, for a budget gun or light plinking...

Check out CDNN as well...they have pretty good prices on NCStar scopes..

I had one of the NCSTAR scopes mounted on the carry handle of my AR. I used it to take three deer last year. It was clear and worked ok. It certainly isn't a AGOG, but it's worth the money for a plinking scope.  Good luck...