"Coin collectors today consider the hobo nickel a numismatic treasure, a tribute to long-forgotten folk artists who often literally carved for their supper. The Buffalo nickel debuted in 1913, but it wasn’t until the Great Depression struck that hobo nickel carving reached its peak. During this period, buffalo nickels were the most common nickels in circulation.
"The sudden scarcity of jobs in the early 1930s forced a huge number of men to hit the road. Certainly some coins were carved to fill the idle hours. More importantly, a ‘knight of the road,’ with no regular source of income, could take one of these plentiful coins and turn it into a folk art piece, which could in turn be sold or traded for small favors such as a meal or shelter for a night.
"The nickel was an ideal coin from which to fashion such a token. The large profile of the Indian on one side and the classic image of the very wide American bison that complemented it on the reverse side provided an adequately sized canvas for the wandering hobo artist to use. It was portable, and the nickel (a copper-nickel alloy) is the hardest U.S. coin in circulation, ideal for carving."
"Hobo Nickels", from Appalachian History.