No clue on what they are worth used. New they were over $200 I believe.
For me there are other direct drive pedals that have been out and are still out there that I'd probably go for first like a Yamaha, speed king, trick, axis that have a bit more adjustability for what you are going to pay. I started off on speed kings ($99 new) went the DW chain route for a couple decades then on to the yamaha 9415 direct drive pedals and won't look back. Love those pedals and paid a $100 for each one brand new. They were an older model but fantastic pedal. Keep your eyes on ebay and they pop up from time to time.