Answer 1

There is no right answer on this question. More expierenced you become in your field more money you can earn.

Answer 2

java

Answer 3

Python. It's simple like Java but is cleaner and cheaper. Things like C, C++ at the beginning may be hard. Or, if you prefer make webpages try HTML5. If you have a mac, Swift may interest you, it's simple and made exclusively for programming mac apps.