That $800 plant isn't even a cactus as advertised (much less a desert cactus). Cactus are native to the Americas. The plant in the photo is a Euphorbia (close

That $800 plant isn't even a cactus as advertised (much less a desert cactus). Cactus are native to the Americas. The plant in the photo is a Euphorbia (closely related to the poinsetta sold around Christmas) and is from Africa. It looks like a cactus but isn't related at all. One way to tell the difference between cactus and these "imposters" is that real cactus have spines protruding from a detachable pad that can be pulled cleanly off (the spines are an evolved leaf and detach in a similar way). The spines of the Euphorbia on the other hand are part of the main body of the plant and can't be cleanly detached. Probably only a few plant nerds really care, but for $800 they shouldn't call it something it manifestly isn't IMOP.