Newegg has some 4-way KVM new for around $80ish, Iogear brand IIRC.
If you're wanting to switch anything BUT old-style VGA video though, the price starts going through the roof - DVI and HDMI KVMs are ALL a ton more per port, which IMO is dumb as they're digital signals not analog and should be EASIER to switch.
I got lucky grabbed 3 used Kvm/usb four port for 60 each with cables and only missing power supplies.
I spent 3x 60 and 3 x 8 or 204. And new they were 3x 170 or 510