Endless Alphabet is free, but users are warned: there are ads in the app, and you'll need to make an in-app purchase to make the ads go away. Most parents will probably want an ad-free experience, myself included. But I actually never made this in-app purchase, and I never encountered an ad, nor did I ever discover a way to go ahead and pre-emptively pay the fee. I might've found one of the app's bugs, but in this case it worked out for my family and me.
Endless Alphabet is fun, educational, and easy to use. It is probably the best children's app I've ever had the chance to use; my four-year-old son, at least, certainly thinks so.
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