When I got mine a few years ago, I only bought dies that were hard for me to cut....circles, hearts, stars, cat, dog, snowflakes, flowers, etc. I felt I could cut strips, rectangles, squares etc and didn't want to invest my "quilting funds" on expensive dies that I could cut myself with ruler and rotary cutter. Of course, every once in a while I would see a die on sale when a quilt shop was cleaning out stock.
also,I have a group of quilting friends and we sometimes share our dies. That is what I do, but only you can decide what is best for you. After all that....I have to admit that I have dies that have never been used. sigh!