It can be relatively inexpensive, depending on which RIR you’re using. There are providers like [Neptune Networks](https://neptunenetworks.org/) or [Vultr](https://www.vultr.com/) that you can peer with from a VPS so you don’t need to get “proper” IP transit in a datacenter.
Oh, interesting -- I assumed you had to have a membership to the RIR directly (APNIC in my case, which would have been upwards of 1000AUD/month). Hmm... Thanks!
Oh, you're right. 1180AUD / year + 500AUD sign-up fee.. Still a bit expensive. If I had a business use case for it I'd be able to justify it, but it's too much for a hobby, unfortunately.
You "just" need to be in their reigon, and have justification. Usual justification is that you have two upstream networks and they'll announce your prefixes (generally with BGP). That's going to cost some more money, but there's specialist VPSes for this these days.
There’s no hobbyist program but neither is it corporate/for-profit only, from what I see.
There are few people(mostly network engineers or researchers by trade and/or business owners themselves) who are assigned ASN to their homelab gears from JPNIC. Knowing the right doors to knock etc.