Starting with one unlocked solitaire (patience) game you must beat each game once to unlock the next of nine other games. All ten games are solitaire variations and are free-to-play once you have unlocked them.
No in-app purchases, just skill at playing solitaire.
Once unlocked a game remains unlocked so you can play it as often as you wish. This is a great way to get introduced to new types of solitaire (also called patience) games.