May 15, 2021
Several people in the comments pointed out existing lower-cost CBT-i apps! This was news to me - I'd searched pretty comprehensively and hadn't found any besides the VA's CBT-i Coach, which is not intended for individual use. They were:
1: Night Owl, seems good but only available for iOS
2: Sleepedy is more of a service than an app, and involves consultations and coaches. When I tried to sign up, it made me take an annoying quiz, click through a bunch of testimonials, and then finally gave me a "Schedule your free call today!" page. Still probably less annoying than seeing an in-person therapist, I guess, and $29/month.
3: Dozy, seems potentially good but still in private beta. Will probably launch in a few months; expected $10 - $30 price point.
Someone mentioned the founder of Dozy was an effective altruist and connected to me through the social graph, so I reached out. He says he's a CS student who dropped out to work on "creat[ing] more accessible & impactful mental health treatments, with insomnia as a starting point". He writes that he's looking for potential co-founders, fundraising help, and advisors in the field. If you're interested, please contact him at firstname.lastname@example.org.