I am PhD student in accounting and I want to learn how to analyze my data on thesis. Which of SAS or STATA is better and how to learn them?

I want to learn STATA and SAS and Eviews completely. How can I learn them and how should I spend money to learn them completely. I am familiar with them to some extent but not complete, therefore I am going to complete my knowledge regarding these three software. Regards, Nasrollah