Well it's OR so I'd get some flip up sights and zero her in. Otherwise don't buy much now, just magazines and ammo, maybe a good sling.
The point is... don't spend much on upgrades now. Wait until you've got a few hundred rounds downrange! You'll have a much better chance of knowing what you need.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
US Army 1966-69, VFW Life Member, Retired Geek