You can buy an AR15 in the $700 to $800 range. Please don't go to a gun show to buy one. My experience has been the prices are somewhat higher for a new AR, and sometimes you can't be sure what you will end up with. I am not sure what chain sporting goods stores are available in NY, but surely there are some good ones. After you purchase a rifle, you can upgrade the trigger group, get a matched barrel or upper, and all the other accessories when you get the money.
I am not sure if WalMart will order a rifle for you, but they may be a source. Different states have requirements that limit sales. Keep in mind you can buy a lower assy. Then, there are no laws I am aware of that prevent you from buying an upper and a bolt carrier assembly mail order. Shotgun News has many suppliers. If you were here in Indiana you could buy a lower for $250 and the sky is the limit for an upper of your choice.
Indy
I am not sure if WalMart will order a rifle for you, but they may be a source. Different states have requirements that limit sales. Keep in mind you can buy a lower assy. Then, there are no laws I am aware of that prevent you from buying an upper and a bolt carrier assembly mail order. Shotgun News has many suppliers. If you were here in Indiana you could buy a lower for $250 and the sky is the limit for an upper of your choice.
Indy