if your feeling bad on the purchase then the only necessary Is mags and ammo the rest will make you feel even worse, like Mike said the sky and your wallet are your only limits
you can opt for rails but they are more of a Tacticool thing for most, you can get rails ranging from ultra cheap UTG for $60 up to half as much as you probably spent on the gun for the top names. Other than looking tacitcool they do serve a purpose as it makes mounting a VFG, Lights, lasers, Bi Pods ect ect ect a lot easier.
better stocks, again from $60 for a Magpul MOE to several hundred dollars.
Pistol Grips, Rail Covers (to protect that investment), Optics, Optic mounts, BUIS, parts repairs kits, better trigger, extra bolt, extra firing pins carry bag,
for me a must was a reloading press so i could afford to shoot it somewhat regularly.
a simple $1000 play toy could result in your wallet suffering from seperation anxiety
basically to get a feel for what you think you would like to transform your rile in to check out the AR picture thread stickied to the top of the page. there is everything from the basic plain jane pure vanilla AR to the most tricked out Rifle with thousands of dollars worth of upgrades and accessories.
as this sits i have about $1450 invested in it. but some of the parts were bought USED but in excellent condition.
