He's got lots of hand-me-down toys from his two older sisters, so something boy-oriented would be greatThey also have a dog, so maybe something without lots of tiny pieces?
You could get a small piece of flat metal and shape it, and carve it into the shape of a two headed quarter.
My 17 month old son LOVES big Tonka trucks.dump trucks, cranes, bulldozers.anything like that:D