Low pressure steam/ hot water exchangers, price?

I recently stumbled across a few Trane model downdraft hanging heaters (look on cozyheat site to see discription). Two different sizes one @70K btu and other @90k btu (hot water). They are used and in fair condition. I pressure tested them and jumpered the motors. They seem to be in working order. Wondering what they are worth.

I just picked up two used Modines for 400.00, one at 86k btu and the other 193k btu. They were in fair to good condition and everything works.

I have a Modine, bought used off of e-bay several years ago, and works great. I only use it when I need immediate heat (storage temp is low) from the boiler. I have a manual by-pass valve from the boiler to feed it directly when that extra heat bump is needed. Don't remember what I paid, but thinking it was around $200.