Including DLC, micro transaction purchases, etc. If you got a game for free, please also list your non-infinite next best.
For me it's Team Fortress 2. $100 total spent on hats and the Orange Box back in the day, 4200 hours plus of fun, meaning 2.3¢ AUD per hour. Initially I thought DotA2 would be my best but it turns out I've spent a lot more money in that game than I thought...
My worst is God of War: Ragnarok. Bought it full price for $95 AUD, only played 2 hours and hated it, meaning $47.50 AUD per hour.
Most...probably Star Wars: Knights of the Old Republic. Bought it when it first came out, and as soon as I beat it, when the credits finished I created another character. I must have beat the game over a dozen times on OG Xbox, 360 and Xbone (I still have the original disc).
Least? Maybe Bioshock Infinite which I bought full price at launch and probably made it less than 1/3 through before I put it away and never touched it again. That or Returnal, I bought a used copy for maybe under $15, played a couple hours before throwing the game away because of how much I hated it.