I didn't do a whole lot of research for you but I did a little and combined it with my own personal knowledge on monitors.
You aren't getting over 60hz without paying $$$. You can however have good response times of 5ms and lower (1ms is overrated and is really only going to be a thing that matters to those who think it actually gives them a measurable edge in fast paced first person shooter games and only in the highly competitive realm like straight up E-Sports)
But you will have a good time playing any game at 60fps with 1080p or higher.
And when it comes to getting IPS it comes down to some very technical and very detailed research for good quality panels and that is hard to come by on a budget.
But here is my recommendation. The Acer G257HU is my recommendation. Getting two of these will put you just above your budget but take note that with B&H unless you live in NY or NJ you won't pay any taxes on the purchase and you will get free shipping. I of course am assuming though that you live in the U.S.
I threw the other Acer in there as a recommendation for a fantastic monitor that costs a hell of a lot less to give you some options. I do recommend that you delve a little bit into the research of monitors and their quality and how they vary.
PCPartPicker part list /
Price breakdown by merchant
Monitor: Acer - H226HQLbid 21.5" 1920x1080 60Hz Monitor ($99.99 @ Newegg)
Monitor: Acer - G257HU smidpx 25.0" 2560x1440 60Hz Monitor ($257.40 @ B&H)
Total: $357.39
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-09-25 02:02 EDT-0400