There's several, just search. $300 is about the cheapest you'll find a 32" 4k though, don't expect much and it'll certainly be a TN panel with a slower refresh.
I've been using this one. (Typing on it right now) Has a display port I wire my mac into when coding for work and run a Linux box on it when I'm playing. It is a nice panel, for what I paid. 32" @ 2650x1440 IPS. I've got it next to an older 30" 16:10 (2650x1600) and it is comparable.
I do wish I could get my hands on cheap 16:10 monitors. My old 24" dell is vertical, which really makes for a nice way to view the web.
My LG is a little over 4 years old (an LG 27MU67, sadly no longer produced), and the only complaint I have with it is that the capacitive buttons are difficult to use by feel. If I could get another monitor that's exactly the same, I'd do it in an instant.
I have a similar LG 27UD68. The game changer for me was taking off the anti glare coating. It's amazing the relief from eye strain that I got once it came off.
I've bought a million of the Dell P series 4k monitors for my office in various sizes, they range from 200-500 bucks or so depending on the size. Even less used or floor model. I have a few dozen and they've pretty much been bulletproof.
