Pac-Man was always sort of like a free-to-play game – you had to pay into an arcade machine each time you wanted to try. Now, 32 years later, it's free-to-play for real on Android, with Pac-Man + Tournaments.
The game includes the original Pac-Man for free, along with a new "Tournaments" mode that offers power-up items and weekly tournaments with chances to win plush toys and other Pac-Man swag. This mode includes new downloadable mazes, which is where the extra costs come in. But if you just want some Pac-Man, that's free.