Solitaire version 2.20 (and up) has switched to being a free download but is ad-supported, with an option to purchase to go ad-free.
Automatic Upgrade
On Android devices we have attempted to identify all users who bought the game when it was a paid download ( prior to September 20th 2017 ), and automatically make the game ad-free for them.
This should work without you ever seeing an ad, as it is identified as soon as you run the game, and will back this setting up so that if you later switch devices and reinstall the game, it will still know.
I bought but I'm now seeing ads!
We have identified a couple of ways that it may be possible to miss out on getting the upgrade for free - so if you originally purchased the game (before September 20th 2017) and you're now getting ads, please get in touch via the support system and we will be able to fix this for you.