Just my thoughts as I can't recommend any specific model.
It depends on what games you want to play. Personally I find AOC 32" 2560x1440 VA or IPS flat panels good and cheap. However, these cheaper models have 60 or 75Hz refresh rates (newer are 75Hz with free sync) only so are better for single-player RPG or something like that where is less movement. For quick online games better will be 144Hz panels but it will require a faster graphics card as you won't see any special difference if a game will run at 40FPS. The perfect ratio is FPS=Hz in 1:1 as one FPS is one screen refresh per second so Hz. This is also why 4k displays are not the best for gaming. The higher display resolution makes you use a better graphics card.
Personally I play on older 32" AOC 2560x1440 VA, 60hz and for me, it's fine for online games too but for some gamers, it may not be the best. On the newer generation AOC, which has my brother, with 75Hz and free sync, it's a bit smoother during quick movement so I guess this is what I would recommend as the inexpensive minimum.
I don't like curved panels. I feel they will disappear from the market in 2-3 years.
One advice. If you have any large electro store where you can take a look at multiple monitors and compare them then just do that. Monitor's specification not always says everything about the monitor. There are additional things like backlight, brightness, contrast, and colors. Of course many things you can adjust from the monitor's menu but not everything.
(copy/pasted that from the earlier thread, I hope you won't ask to delete this one too
)