I'm taking classes right now to learn game programing, but I'm wanting to create games for several different platforms, including iPod, I pad, android, flash and so one, I don't have to but all the licenses to do this do I? And if I don't which should I invest in?
You might benefit from taking a look at the license comparison as well as the shop pages on Unity's website. Here are links:
The license comparison tells you exactly what each licensed Unity component gives you, and the shop page lets you play around with adding different versions and components to see what the price tag would be.
The short answer is that if you want to target multiple platforms, then yes, you do need to buy multiple unity licenses. Not everything is free, unfortunately...