Prices have been slowly creeping back up over the last few months, but the usual suspects are companies like Palmetto State Armory (who recently had a $280 kit before shipping, tax and transfer fees) and Del-Ton.
Palmetto State Armory is specifically what I was referencing, but last time I looked was also 3 years ago
Buy an anderson lower and a cheap steel barrel palmetto arms upper. Getting it below $300 can usually only be done when parts go on sale, but it can be done.
Thats kinda my point, its not a gun, its parts.
You can't walk into a store with $300 bucks and walk out with a useful thing.