What is the best AR-15 for the money?

For value, look at a complete rifle from a reputable maker — Ruger AR-556, S&W M&P15 Sport, or an Aero Precision build all run reliably without breaking the bank. If you can stretch, BCM and Daniel Defense give you duty-grade bolt/barrel quality for a gun you might stake your life on. Spend on the barrel, bolt carrier group, and a quality optic; skip gimmick furniture. A reliable mid-tier AR plus ammo and training beats a fancy rifle you cannot afford to shoot.