I paid around $50 and $75 for my two wg4s. Both were garage kept and not running. You could get as high as $300 depending how well it runs and looks and how long you have to wait, and what the outboard motor market is like in your area. The least I've paid is $15 for a Wizard missing a prop shaft and carb cowling and the most I've paid is $125 for one in good shape.
Lots of variation in motors and lots of variation in prices. A motor that
starts,runs,pumps and has factory like paint, handle grips, starter grip
and decals is a different proposition than one that got left outside for
a few decades. Someone wanting a "daily driver" likely wants a classic era
or newer outboard that dealer can still supply parts for. The demand for
"antique" and older outboards is mostly from collectors and fixers often
retirees looking for something interesting to do on a limited budget...
I have been given and have given away outboards...so price can be zero
Once or twice old outboards and parts have mysteriously found their way
into my pickup at a meet when I was not sufficiently vigilant.
Price for an old outboard can be hard to pin down.
Local metal recyclers buy old outboards as "mixed metal scrap" but will
not sell them at any price. The buy low and sell high formulae for
business success seems not to apply.