You can pull a used one off of a used car or truck for $5-$10 at a junk yard. It is a messy job, but, someone has to do it.

Usually the only reason someone would want to get rid of a functioning pan is either it was warped or bashed and it leaks.

I would look for a junk yard dog truck resting on blocks or rims (I would use jack stands though) with its front axle gone. That should be easy to find.