Now I think that is a cute little block plane and I personally think that it would be worthwhile iffen you spend 10 - 15 minutes wire brushing the dirt off/out of it and then give it a light coat of oil. Nothing more, it doesn't have to actually work, only to "look used", cause its a nice little "decorator piece" for someone to take home and sit on a shelf.
Iffen you decide to sell it at a flea market or garage sale, .... don't put a sticker price on it. But the 1st person that picks it up and looks it over with interest, ..... tell them "$20". And iffen they start to put it back down, quickly say "17.50". And so on n' so on, keep dropping the price at $2.50 a clip, and I'll just betcha they will take it home with them fore ya get down to a $5 bill.