Help for second monitor.

I am currently using two monitors on my desk. My 28" 4k monitor and some Compaq 17" 8:5 monitor which is only 1440x900. I am getting a dual vertical monitor mount for christmas and would like to get another monitor to replace the Compaq. I would love for it to be as close to 28" as possible and be at least 1080p. Only thing is that I want it to be under $100 . If you know of any monitors, let me know. It doesn't need to meet my requirements, but the closer the better!

I dont know of any new monitors on sale, particularly that large, for that price, sorry.

For your criteria:
Cheapest on the market = $160
Cheapest I would buy = $180

Well I found the cheapest of all! Grandma gave me her old w2207! (22" 1680x1050). Not the best monitor out there, but you can't beat free.