I have an older Blue Ribbon English saddle that's a 17" with reg tree. Okay condition, but needs oiling to be supple again. I'll sell it for $120 shipped in the U.S.
Also have an old Smith Worthington 17 (or 17 1/2") saddle with a M spring tree. Decent condition, super comfy-- I've used it for the last year b/c it's that comfortable! $250 shipped anywhere in the US.
I also have an 18" HDR Advantage AP saddle with a W tree for sale. $380 shipped w/in the U.S. For it.