Tricky question.
I'll take a shot. I wouldn't pay more than $100 for it!!
ok...seriously... In what is only MY opinion, I would say around $800-$1000 if complete and working, in the real world. Assuming it is not a rust-bucket, hard to tell from the pics.
I'm asking on the lower end of that range for my Glasco Coke slider. Mine is not embossed, but it is in better cosmetic shape than this one. I figure the two balance each other out a bit.
Jim