Photoshop costs around $300
There is a free program that is almost identical to photoshop. I've used it for about 7 years now. It's great. It's called Chasys Draw IES
http://www.jpchacha.com/chasysdraw/download.php
This is free and versatile. You can add fonts and tools. It's user-friendly and the designer continues to update it.
I second pgessert's suggestion of checking out thebookdesigner.com and other resources on design.