The game is free for both iOS and Android not including in-app purchases. The game is similar to most guessing games.
Here you have to match the letters in order to find the right combinations for a word. The fun part about the game is the themes that change in every level.
The game is capable of giving the player hints in case they get stuck but for them you have to pay from your earned coins in the previous levels so they should be used with caution.
You can check out Wordbrain Themes Answers here