Is there any app to check my pronunciation?
FluentU (Android/iOS)
Not only do you get to see the language used naturally, but you also get to hear native pronunciations of every word. Anywhere that you see a word, you're able to check its definition, hear an audio pronunciation and see the word used in other videos.
Is Elsa Speak worth it?
ELSA Speak is an excellent app for what it is meant to do: practice American English pronunciation. The lessons are quick so you can do as many or as few as you want in a day. Even though you are practicing the same skill, there are lots of different exercises that can help keep it interesting.