congrats, Rambo, you'll enjoy your RRA!
USGI mags, of varying manufacture, are available on the EE...poke around...I bought 8 with a buddy, @ 16.00 a pop. That's a real good price, but you should be able to snag 'em for around $20, depending on how lucky you get.
If you're gonna shoot from the bench at all, try and pick up a USGI 20 rounder...also, the DPMS waffle 10 rounder I have works great, but the bolt hold open doesn't work with that mag...I've never had a FTF with it, though, even after at least 1000 rounds...I use that mag in every AR I use, every time I go shooting.
Scope rings, depends...I like the ARMS #22, since it allows me to take the scope off in a matter of seconds, and to put something else one as quickly. For a more permanent solution, I don't know...my good bolt rifles have the Leupold one piece windage adjustable ones...but that's not an option on the ARs. You'll have to wait for the scope and ring gurus to answer that one.