In last several days, I've been making an investigation about test automation tools for the mobile applications. I'm working in a cooparation developed mobile applications and need to automize some kind of test cases that i'd written. but did't get an enough information about which tool should be used for my testing process. the tool that i'm looking for can have following properties.

1) that tool doesn't have to be professional.it's enough for just mobile applications so the price compatibility of it is an important issue actually=)
2) it should support versions of ios,android and windows.. especially it's important to support ios and android.
3) for me, the main reason that i want to use test automation is actually running the functional test cases. For instance, in a banking application, i'm making a money transfer and after finishing that process, i need to check whether the balance of my account decreases or not, or if the balance of my account is decreasing, does it decrease rightly?. Can i automize these kind of test cases by using the tool.?

these 3 steps are motto for my tool selection. which tool should i choose?