I've never spent more than $75 on a monitor. I only buy used. Monitors depreciate like crazy and businesses are constantly getting rid of them, even when they're only a few years old. Yeah, you aren't going to get some 9001Hz 10K giga-OLED whatever, but I'm a programmer. If it displays text with reasonable contrast without hogging my whole desk, it does everything I need it to do.
The most expensive one - the $75 one - is a 24" 1920x1200 IPS display with HDMI, DP, VGA, 2x DVI, S-Video, and YPbPr composite. Never seen those last two on a monitor before, but there they are. I don't use that display as my main one anymore, but I keep it around because it's awesome and it plugs into literally anything.
The most expensive one - the $75 one - is a 24" 1920x1200 IPS display with HDMI, DP, VGA, 2x DVI, S-Video, and YPbPr composite. Never seen those last two on a monitor before, but there they are. I don't use that display as my main one anymore, but I keep it around because it's awesome and it plugs into literally anything.