GIMP is a free open-source image manipulation program. It functions, essentially (with a few minor differences) exactly the same way as Photoshop, which means it gives you exceptional flexibility and control over image manipulation. There are tons and tons of excellent tutorials online for how to use GIMP...just about any effect you want to create, somebody has made a tutorial for. Any brush or font you can load into Photoshop you can also load into GIMP.
There is some learning curve involved, so if you're totally new to image manipulation, or if you've had no experience with Photoshop, don't expect to be producing quality results any time soon. It can be a little tedious learning all the right tricks, but once you get it, the skills fall into place. If you have a deadline for producing a great cover for your book, you might be better off hiring a cover artist for your first few covers while you take the time to learn to make your own. Covers are so important, you really need to have a good feel for not only the software but book cover design in general (i.e., be familiar with what works for various genres). It's not a skill you can expect to learn overnight, but you definitely can learn it!
There is some learning curve involved, so if you're totally new to image manipulation, or if you've had no experience with Photoshop, don't expect to be producing quality results any time soon. It can be a little tedious learning all the right tricks, but once you get it, the skills fall into place. If you have a deadline for producing a great cover for your book, you might be better off hiring a cover artist for your first few covers while you take the time to learn to make your own. Covers are so important, you really need to have a good feel for not only the software but book cover design in general (i.e., be familiar with what works for various genres). It's not a skill you can expect to learn overnight, but you definitely can learn it!
