Astraware Mahjong gives you the option to play with ads for free, or to make a single in-app purchase which meanss no more ads, and all the custom features are available.
We call this option 'Go Deluxe!'
It will unlock the game for all of your devices that are linked to the same store account.
Some players are fine to watch ads before a game (or build up extra tokens in advance) to play for free, but the option to Go Deluxe makes it distraction free forever. Either way helps to support Astraware!