I used to play EVE Online, there was a monthly sub, and you could give others a monthly sub in return for in-game currency, and there were skins. Probably spent 1-2k over about 10 years ish. That game is so infested with microtransactions now it's disgusting.
I wouldn't call myself a WOW player, but I did buy all the expansions, plus the monthly sub. That's probably been about £300 over 10 years ish. But only played for about 6 months of that, so that's pretty bad value.
I played BF4, that had a 'season pass' which included content that should have been included at release but was marketed as DLC instead. That was about £100.
I don't mind a subscription for an mmo, to some extent it keeps the kids out, but microtransactions and dlc I'll never do again.
I preordered Diablo 2 Resurrected. That was about £40.
I normally don't like preorders / kickstarters / alpha/beta / early access.
My standard Steam search filter is: on offer + under £20.
The game I've played the most is Subspace Continuum, which is free, lol.