Hey everyone, new to this site and was just looking into possibly upgrading my ar 15, all I have done is a crappy quad rail that doesn't line up right not to sure on the brand, and by lining up right I mean the receiver rail with the quad rail, and a vertical fore grip that isn't comfortable and is somehow not straight and kinda cock eyed. I know I for sure need new optics and was thinking bout just doing iron sights, the stock red dot that came with it is crap and was thinking of a new trigger assembly and then a new upper and floating rail, can anyone point me In the right direction for any of these products that are good and not gonna break the bank, thanks. Btw, this is my first gun I've bought and first ar 15 I've ever owned.

Update, I was looking at an aero upper, are those fairly good?

OP, I see you're calling this a C15. Is this a Bushmaster "Carbon 15" by chance?

The best in overall cost for a good Upper without breaking the bank is check out PSA(Palmetto State Armory). They're listed in the Industry section of this site, along with a Forum Page. Good sales all the time, quality parts, and good CS if you have a problem.

. They have low cost PTAC uppers that work well, but definitely plinking material only. Great pricing starting less than $200.

 Freedom models are their midgrade quality builds of using better materials using mostly stainless steel barrels and mid-length gas ports, generally w/18" barrels. Prices range between $200 to $300

 Premium lineup is their best lineup using top grade materials and barrels. Prices $250 to $450 with many options of barrels, handguards, sights, etc.

Then they have what I would call Premium "Plus" where you get the Cold Hammer Forged barrel models. Prices around $275-$350 when on sale or special blems.

I've assemblied 3 rifles using PSA complete Uppers and/or using their Lower Parts in building Lower Receivers from another Company. They are good stuff, but it's your money. Spend it where you want.  

Now, if you do have the Bushmaster Carbon15, I would just save and get a new lower as that plastic will break at the front hinge pin area. Maybe not today or tomorrow, but it will break if you're not careful when doing a takedown for cleaning or possibly from the recoil stress.

Right now it's a buyers market for getting GOOD / EXCELLENT Lowers and Complete Lower Assemblies for less than $200 and have shipped to your local LGS. OR, learning to build a new Lower the way you want with a good trigger system.