A lot of folks say this is what you want, a Classic Army AG36.
http://www.arniesairsoft.co.uk/revie...uct/587/cat/47
Better than the Star or the Smokeys version. As for finding one though you will need to do the legwork of getting out to games and meeting folks, and also getting the little age verified tag so you can check on here too. I don't ever really recall seeing one for sale, but I haven't been looking for one either so I might just be tuning out the info.
Whatever you do start saving the cash now, and keep it put aside, if you do run across one you don't want to "oh can I pay you in June" on something that's uncommon.