In Illustrator, you can design patterns, complex graphics and work with type. You can learn to design printables fast with the Basic Printable Design Course from Printable Crush. Illustrator is a highly in-depth program, so taking a course is a quick way to learn the basics.
Another handy tool for printable assembly is a score board. You'll use it to make creases in paper for easy and precise folding. Don't feel the need to buy all these items at once. It takes time to acquire all the tools for printables, but in the end, you'll find that the investment will be small for a fun and creative hobby or business in printable design.