Hackathons, although fun and a great way to work with cool people you wouldn't do normally, is not cheap.

A weekend hackathon I attended costed them 50k AUD... Absolutely NUTS.

Finding space and the people are the two hardest elements.

Space is extremely expensive, thus without sponsors, it'd be quite difficult starting out. So cafes, restaurants or public spaces are the only option. However, much time is spent simply scoping out the places to see what capacity they'd hold.

People is the next difficulty. If your city isn't large, you'd probably not find people at all. Advertising is a massive chore, and finding which communities contain your interest groups AND have people in the area is time consuming.

Personally, I do not thinking hosting is worth it, unless there's absolutely nothing else nearby. If there's already a book club, just join that and chill. Leave the hosting stress to someone else if possible