Yeah i just paid USD25 for the roll20 tales from the loop module. I already own the hardcover and pdf, but it has preloaded all the handouts, art, maps and the like for the approx 5 sessions in the core book mini campaign.There is another category @Morrus that I think you left off - Virtual Tabletop ready book.
I've bought several 5e books. More than I bought for 4e and getting pretty close to more than I bought for 3e. I'm not a huge buyer, by any stretch, but, I am buying semi-steadily. Only trick is, I haven't actually bought an RPG book since the Core 3 were released. Everything I've bought has been integrated with Fantasy Grounds.
Now, for that sort of thing, I have zero issue paying at least cover price. Presuming that the material has been properly inputted into Fantasy Grounds (and, by and large, it is), I'm very willing to pay for that. So, new release hardcover is what, about 50 bucks (give or take?)? Yeah, I have zero problem with that. For the time saving and the huge amount of time I'm going to use something like, say, Candlekeep Mysteries? Cheap by the dozen really.
Frankly, I can't find a cheaper hobby. Five people, playing 3 hours per week, probably about 45 weeks/year and it costs me maybe 50 bucks? It's a freaking steal and I wouldn't be terribly bothered if they upped the price.
That's 5USD a session for what's saved me hours of snipping, uploading, organising etc.
You could count the original cost of the book, but I've already many hours of enjoyment reading it on it's own merit so I consider it paid for.
Even buying hardcover novels to read is a more expensive hobby, as after you finish those you don't have a game you can play.