For example, I'm sure the average joe doesn't know just how expensive calligraphy pens can be, or how deep the rabbit hole goes on video game speedruns.
Improv theater. Most theaters, even in smaller areas, require 3 or 4 classes before you can audition for a team. The classes usually run around $200-$300 a pop. Once you're on a team, you're required to pay for a coach and sometimes a practice venue. Smaller markets are easier to get onto a team than bigger markets, but there's generally a lower ceiling. Those that are really serious usually move to New York, Chicago, or LA for a chance to do it professionally, which very few people get to do.