Gary Duke has a very rare cactus up for auction on Instagram.
It is a unique variation (largest Echinocereus plant in the family) that only occurs on White Sands National Monument, a national park. The dunes are slowly overtaking the population and they will be extinct in a few decades. You can bid for the cactus in the comments on Instagram at https://www.instagram.com/p/CrOZdVdLVvh/
(Looks like you need to have an Instagram account to do it).