I want to build 16" flat top low profile gas block that will shoot  1 moa at 100 yards. Is there a list of companies out there for reasonable price, Is there any  companies that  sell complete ar kits like cold arm hands.Thanks for your help

I'm not all knowing, but I don't think it's likely that you're gonna find that kind of performance out of a kit gun barrel & at a reasonable price from many sources. Granted there are other factors involved like ammo, shooter ability, etc., as well. I would, however, challenge you to solicit the MOA guaruntees from various kit makers & see what they advise you reference matching your requirements. There are several companies that sell complete kits minus the stripped the lower. If you want around MOA you need a good barrel & good ammo which is likely gonna cost you more than you want to spend.

Most ARs kits or otherwise are perfectly capable of doing 1 MOA no problem.  Del-Ton is where I would look first but there are also kits at Model1sales and akpartskits.com (unless you have a clue what you're doing stay away from akpartskits.com).  Have fun!