Well,
i think you are a bit novice on game develop, so mi piece of advice is this:
if you are short of money, download Lite-C free version, it comes with MED and SED (model editor and code editor, there is no WED on Lite-C free),
and practice, make small games or part of your project.
When you feel comfortable with programing or making art stuff (or you have joined a team), then you can think about buying a better version. As you learn and start to make things, you will know for sure what tools you need.
Buying a Pro edition will not make the game for you, anyway.
You need to learn how to use it.