Sorry if this isn't the correct way to post, but I have lots and lots and lots of rigid foam insulation. Smooth paintable fiberglass on both sides. 56"x20" and 36"x20"
That would be the equivalent of $16 for a 4' x 8' sheet, which is around half the price of similar material new. Not bad, though the small sizes make it generally less useful, and you may want to consider a somewhat lower price if you want it to move quickly.
That said, I have no idea what building supply prices are like in the Seattle area.
For my next feat, I will require a volunteer from the audience! Perhaps this tiny ad?
grow your own garden and build your own home in the gardening gardeners program