Free forever, no in-app purchases.
If you feel like dropping a bit of gold towards the rent, that works too.
Drop gold and you see exactly what everyone else sees. No paid items, no top-up bonuses, no skins to unlock, no VIP queue, no whale leaderboard.
This page exists for one reason. Some people finish the run and want to know where the tip jar is, and I would rather they did not have to go hunting for it.
The first two work out at about twenty dollars a year, so almost all of the cost sits in the third row: 12 pages in the Chinese edition, over 40,000 characters, citing close to a hundred classical works and more than a dozen modern studies, with every reference checked and plenty of it reworked. The version number is still low, so there is more to come.
As for why the third row carries no price: put a number there and this becomes a paid game, which is a different thing entirely.
If money is tight, keep it. This game is free forever and freeloading is an officially supported playstyle. There is a whole section of this site about it being fine to have nothing left in the tank. Putting you on the spot on this page would make a liar of it.
The site is stuffed with sources, dates and study citations. I checked them and had someone check them again, and there will still be mistakes. Tell me which page, which sentence, and what is wrong with it. No need to dress it up.
No pitch required, just send the link. This server does no marketing and buys no ads. The only way anyone finds it is somebody passing it along.