Lotta great options above!
Assuming you have magazines and ammo, I have to agree with Dillinger and lonyaeger on the sling. You really can't go wrong with a quality sling that simplifies things for you. Problem is there are so many types and you can't try them all.
I thought I was happy with my sling until I stumbled across a used CQB Solutions 3-point at a gun show. It was only $10 probably because it was for a fixed stock but one cut in the right spot and a short strap of webbing and velcro modified it for a telestock. Amazing sling! Spectergear.com now sells these slings and TheWilderness.com sells the Giles sling which is pretty much the same. Both are about $35-40. Condor sells something very similar for about $15, I was just in my local Army/Navy surplus store and the Condor looked surprisingly good.
Of course if you don't like a 3-point there are other options...