Riot Games pulled what will probably turn out to be the most infamous monetisation scheme in their history by adding Eternals to League of Legends. It is basically stat tracker with achievements that costs up to $1.750 for all champions.
League of Legends switched from regular point grinding and unlocking things to a loot box based grind at one point and also introduced paid loot boxes with a handful of skins exclusive to them.
One could think this would be the worst thing they did with League since Riot are considered one of the few developers who don't step into the egregious monetisation territory. All of this was changed with the latest PBE update which is set to go live with the next (9.17) patch by adding Eternals.
Eternals is basically a fancy name for a paid stat tracking system. Normally, this wouldn't be that much of an issue since Dota 2 and CS:GO both used it via skins or by other means. What neither of those two games did, however, is giving those systems obscene price tags.
There is a total of six Eternals in League of Legends and each of them track different stats. They are sold in sets of three and with a little bit of maths, players calculated the price to cost around $10 per champion to purchase all six Eternals.
As for Riot Points (RP), which is the currency purchased with real-life money, it would take 246.500 RP to unlock all currently available Eternals for all the champions in the game. That amount of RP translates into roughly $1.750 and that's not even the end of it. The official post explaining Eternals has already announced new sets planned for the future.
Players normally pick a handful of champions they play most of the time but with prices going as far as $10 per champion for a set of six Eternals, they are still bound to pay way more than the price of several AAA titles in the future. All that for stat tracking and a few emotes.
Keep in mind that the more Eternals arrive to League, the higher the price of tracking all stats for your champions will be.