Me and my partner in crime on Cod ordered up Asus monitors, 2ms, decent spec and I don't think they were over £200..
If it's for ps4/Xbox you don't need anything over 60hz, and an Asus or benQ wouldn't be a bad buy.. If it's for a pc that can handle 120 or more then you'll have to troll out the specs more..
You need the ms response as low as possible, 1-2 seconds is where you wanna be.. Fast response monitor, hardwired machine = melting the opponents.
My tv in gaming mode was 12 or 20ms response and I would get bummed, the 1-2ms monitor makes that much difference it's like night and day..