Horchata is legitimately that good. I've never had it bottled, but it's relatively cheap and easy to make. If I had the fridge space I'd have two jugs going at all times.
Grind/blend the tiger nuts in water. Pour all of it into a cotton bag (like people use for Greek yogurt) or cheese cloth over a bowl, then squeeze the hell out of it until all the tiger nut milk is out. I still use a cotton bag, but cranking it with a press is WAY easier, faster, and more effective.