I am told by junkyard workers they are amazed how many vehicles now go to the crusher with "virgin" factory full size spares in the trunk!
Also, since so many new car buyers summarily install aftermarket wheels taking substantially different tires (and in sizes the factory doesn't approve of...) there is sometimes a very good supply of "used" tires and wheels that in reality are brand new. Purchasing and using these carries no shame in my book.