I looked at http://www.cnet.com/topics/monitors/best-monitors/ and the prices for such high end displays are 50% more than your budget.
HOWEVER I use a 21 inch 1080p IPS display for work and it was under 200. Not retina but for me quite usable for many hours per day.
If I was to do this again I'd go to a store to shop as well as start done the list at http://www.amazon.com/gp/bestsellers/electronics/1292115011/ref=pd_zg_hrsr_e_1_3_last to find IPS displays.
Bob
My macbook pro with retina recently had some incidents, causing it to be parted out for cash. I bought a new macbook air, but really miss how good looking the text was on a retina screen.
I am considering buying a desktop monitor to hook my Air up to, but I don't know if there are any monitors that can have crisp text that would look at all close to the retina, or even close to my air.
Does anybody know any really nice looking desktop monitors that may go on sale on Amazon for under $400??

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