Yes aloe vera cactus...
You can buy it in the usual garden shops - often in or near the herb section and it might have a blurb on the label about healing properties through the ages or something.
If you have a friend who has one - you can grow it from one of the cactus "pups" that appears at the bottom, and I'm pretty sure if you just cut a big leaf off, bury the bottom half in sand (let the end dry out and seal over a week first but I think that's optional). it will grow. Like geraniums grow from cuttings.
There are lots of different aloe cactus.
Only one Aloe vera - well there might be a few variations but Aloe Vera is the one you want.
I usually cut the prickly sides off it before I roll it or slice it down the middle to get the good stuff out.