Second monitor (again)

After six months with only one monitor on my computer, I finally replaced the small one I gave away for a nice 24" Benq. I had been thinking about holding out for a 4K monitor but the prices, which appeared to be dropping quickly last year, no longer seemed low. I can't get much for under $550. Someone told me that the quality of the cheap ones that were popping up was highly problematic and no one seems to be selling $300 4K anymore. I'll wait. This makes the multi-tasking (editing while scanning or watching Netflix with William while scanning or editing, or writing while capturing, etc) much easier.