The tuba, the biggest and lowest-pitched among the brass family, can run from around $2,000 for beginner band models to more than $20,000 for specialized professional versions, says Martin Erickson, a past president of the International Tuba Euphonium Association. People with “nefarious” intentions, he says, probably try to resell tubas or use them in other bands. “You don’t expect tubas to fall into that sort of thing.”