Solitaire Collection is a free app that offers three of the most popular solitaire card games - Klondike solitaire, free cell solitaire, and spider solitaire, all in one place. The app also offers well-designed tablecloths and cards looks to keep the game visually interesting.

One of the unique features of Solitaire Collection is the daily challenges, which give players the opportunity to accumulate points and win gold badges. The app also plans to add TriPeaks Solitaire, Pyramid Solitaire, Heart, and other card games in the future.

While the app is free, there is an optional subscription available for US$1.99 per month or US$9.99 per year. The subscription offers bonuses such as removing ads, receiving free coins daily, and gaining more XP after winning. However, subscriptions renew automatically unless turned off 24 hours before the end of the current term.

Overall, Solitaire Collection is a great option for fans of classic solitaire card games who want to have them all in one app.