These are the fibers that I like best for Spinning 1-4. You definitely don't need all of them, and these aren't the only ones that work well. To start out, I'd get either one bag of Dyed Corriedale or one bag of Carded Coopworth, as well as one bag of something that just makes you excited to spin.
For Spinning 3, I particularly like the Special Gotland Bundle because it allows you to experience both commercially carded and commercially combed prep on exactly the same starting fiber. This is a rare chance to really get to directly compare the way the different preparations spin and affect the finished yarn!