Acer.com has the 21.5" Aopen 22CX1Q Bi 1080p LCD Monitor for $74.99 - $15 with promo code PRES20 = $59.99. Shipping is free.

• Resolution: 1920x1080, VESA Mount: 75x75
• Panel Type: TN, Response Time: 5ms
• Refresh Rate: 60Hz, Contrast Ratio: 100 million:1
• Inputs:, HDMI, VGA

Staples.com has the 27" AOC 27B1H 1080p IPS LED Monitor for $94.99 with free shipping when you apply coupon code 27019 at checkout.

• Resolution: 1920x1080
• Type: IPS Panel LED
• Refresh Rate: 60Hz
• Contrast Ratio: 1,000:1
• Inputs:HDMI 1.4, VGA

Amazon has the LG 27UL650-W 27" 4K UHD LED Monitor for $349.95 with free shipping.

• 3840x2160 resolution, 60Hz refresh rate, 5ms response time, VESA mountable, 2x HDMI, HDR10, AMD FreeSync