Where can you get a replacement compact spare tire?

Where can you get a replacement compact spare tire?
Probably the best and cheapest place would be a wrecking yard.You do need to exercise caution regarding the age of the tire (even spares). The current recommendation is that no tire be used that is over 10 years old. I've had two compact spares fail even though they had never been used before. All tires manufactured since 2000 have a date code, so it should be easy to determine the age.