Investing Monthly

I would like to create a system code. Content of this system should be: Invest in ETX every month 100 US dollars. Furthermore, I would like to evaluate from the historical data when it is better to invest. At the beginning of the month, in the middle or at the end. Can anyone help me or does this afl code already exist?

The Users' Guide gives you example code that does just what you asked for:

Thanks a lot! Have a good day!