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.
The great thing about printables for personal use is that you don't need to have a fancy printer or pay a printing company a fortune. Simply print graphics at home with an inkjet or color laser printer. You can find a printer for as little as $60 or upwards of $2000. Don't think you need an expensive printer to create incredible graphics. A printer in the $100 range should work fine.