When I was in Germany, I saw vending machines where you could buy contacts. Sure, there's a lot of possible values, but they probably only stock the most popular ones.

Here in Japan, you can easily buy contacts from optical stores. They have several shelves behind the counters where they stock many varieties. Sometimes they even put a bunch of unsold/unpopular ones out front for 1/2 off (a lot of these are color contacts). I get mine online; I don't need a prescription.

One thing I did notice, as someone with astigmatism, is that the number of possible values is less here. My axis back in the US was 100, but here I have to use 90; they just don't carry them in all the possible axis values here.

Not aisles upon aisles but yeah for instance in Apotek, a big pharmacy chain in Sweden, there is usually a whole wall of them with little drawers to pick from. As sibling comment mentioned there isn’t every combination available so presumably you have to special order some if you have some weird combination but for myself who never had astigmatism at all it was perfectly fine.