There are plenty of options available for gaming monitors under $200. Usually, the monitors under $200 feature TN panels which are generally known for their speeds at an affordable price. However, for speed, you're trading off viewing angles here. It shouldn't be a concern if your primary requirement is gaming only.
Here are my recommendations.
Asus VG245H (the best option)
Dell D2719HGF (a 27" option which I won't recommend as it's a 1080 panel, unless you strictly need a 27" screen)
Acer XFA240 bmjdpr (A good gaming monitor that features G-Sync)