Word Ball Pool is a word puzzle and a pool game. You must pocket lettered balls to spell words.
You get instant access to all rounds and all app features. The main round includes over 7,600 words. You get full access to all themed word rounds, like US presidents, TV shows, types of candy, etc. You also get 6 rounds featuring sight words for kids in preschool, kindergarten, first grade, second, grade, and third grade.
The only in-app purchase is for "hints" to help you solve the word puzzles, but you can always get hints for free by tweeting @wordballpool.