A hobo nickel is when a sculptor heats up the face of a nickel and carves it into a figure of someone else, usually a hobo, hence the name. Technically, it's PMD, but that's the same as calling a counterstamp PMD. They are highly collectible and the price depends on the kind.
When a nickel is turned into a hobo nickel, it goes from a numismatic item to art. Being art, the value depends on who made it (sometimes) the quality, the detail, the design, etc.
Are you sure about the heating up part? That's a new one on me. Here are a couple of my Hobo Nickels. The 1935 is a modern carving and the 1936 is an original carving.
I agree with others its really artwork, not a coin, when it becomes a hobo nickel. You have to be extremely careful, since these have been "remade" for 40 years now since they became popular. The originals from the 30's are very desirable, but its very hard to prove they are an original without being a real expert. Short answer, prices vary wildly, and its a very tricky market where I would not spend any serious money without a very experienced collector guiding me. Edit: Another way to think about the danger, is it is just like the toning market. How do you PROVE it is an original and not a reproduction? Effectively a reproduction IS an original if created the same way, without further proof.
