"without extra recipe" what does this even mean? These phrases are getting more and more bizarre.
I would also translate it as prescription. It is probably meant that one can buy medicine without prescription.
Oooh, that makes more sense. In English that would be an idiom for "over the counter"
I agree. Propositions in Germany usually don't use the same construction in English and for the most part you can't directly translate them word for word like here on Duolingo. If you were to say "I am on the bus" and use auf/an for the translation then a German would think you were literally on top of the bus. Instead you say "Ich bin in Bus", which I think actually makes more sense. It's the same issue in French, my favourite being "Je suis fini".