Best Buy offers the 10mm-thin HP Elite L2201x 21.5" 1080p LED-Backlit LCD Monitor, model no. LM917A8#ABA, for $89.99 with free shipping. That's tied with our expired mention from six days ago and the lowest total price we've seen. (It's a current low by $18.) It features a 1920x1080 (1080p) native resolution, LED backlight, 5,000:1 contrast ratio, 250 cd/m² brightness, 16ms response time, and more.

Of note, this has a DisplayPort only, so you'll need an adapter for other connections.