There are now a great many options for optics on an AK. Years ago, when dinosaurs roamed the earth, it was a Kobra (with cyrillic markings) or nothing.
Wondering if anyone buys Kobras anymore, or if everyone just gets an Ultimak mount and a dot, or mounts a J-point on a weaver mount, or......etc.
Edit - what would be a fair price to pay for one second hand? A guy at the club has one for sale @ $75 or so, never really used, just stored.