I got these with a set of wheels I bought and already have a set of studded tires. They're in good condition with lots of rubber left. You'll easily get another two or three winters out of these at the very least.
Size is 700x38c (40/44-622)
$50 for the pair. It'll cost you more than double this for a new set and judging from the wear I'd say these have barely been used.