Aloe vera is the correct name, having been published by Burman a few days before Miller described the same plant as Aloe barbadensis almost Two Hundred and Fifty Years Ago (1768). Because the earlier publication date takes precedence, the name Aloe vera is the accepted name for the plant. I know of no one selling an Aloe vera Burman, or an Aloe barbadensis Miller. They are the same plant. No one is cultivating one versus the other. The names are synonymous.

You know, I have to give you credit just for asking the question. I have never seen this specific issue raised before. There are two primary phenotypes in cultivation, a spotted-leaf orange-flowered plant some call Aloe chinensis, and a somewhat larger version without leaf spots and yellow flowers which may be the closest to the ancestral Aloe vera. It has been cultivated for four millenia, so it is hard to sort out its true ancestry. No wild populations have ever been found, and the plant may be of hybrid origin. Genetic analysis suggests it is closely related to a number of Aloes from Yemen (Socotra), Somalia, and Sudan.

Brad

Locally, Lowe's and HD both have nice sized Aloe vera plants for $3-5. Not sure what you mean by usable, but the leaves are 10-inches or so long and there are at least 5 leaves of this size on each plant.

We have the plants available all year long in SW Florida since we rarely have a freeze.

Edit - I just realized that you may have phrased the question as you did because SO many places call all of their Aloe varieties, Aloe vera. That can be confusing, so you wanted to be sure that folks knew exactly which plant you are seeking. Again, our BBS are selling them. Perhaps you can find one on clearance since winter is coming? Good luck!