> it cost me something like 30 bucks and 30 minutes of my time

It cost you 30 bucks and 30 minutes of your time to pass the exam, not to learn how to drive. That’s what is costly in France, because it costs ~€50/hour to have someone teaching you how to drive. People usually take at least 20 hours to learn, which is 20x50 = €1000. If you already know how to drive you can bypass the whole process and pass the exam as a “candidat libre”, which is free [1] (but it’s hard to get a slot).

[1]: http://vosdroits.service-public.fr/particuliers/F2825.xhtml (in French)