There is a unique opportunity to make bets in solitaire levels! Before a level starts, you can choose the size of the bet: Standard, Double, and Maximum.
The difficulty of the upcoming level does not change depending on your bet, only the cost of entry and the cost of boosters on the level change. It's worth it, though: the higher the bet, the higher the reward for winning the level! When you win, you increase not only the number of coins you get but also the number of points in active events.
You can change the bet amount before the start of a level by tapping the Plus and Minus buttons. Remember to change your bet before starting the next level if necessary, otherwise, your previous bet will automatically be applied.