If you're interested in e-publishing, you'll come up against the problem of providing a cover for your book. You don't actually have to - Amazon and other publishers usually provide a generic cover.
But they're so . . . generic. So what do you do?
If you have skill and a program like Photoshop, you've got a beginning. You do have to tread carefully, though. You can't just pick up a photo from the net and slap that on as a book cover. That's copyright infringement, and you could wind up having to pay a big fine.
So you need either photos you already own (because you took them yourself or the person who did has given you permission) or photos you buy. This can get pricey, but there are a host of online suppliers of royalty-free photos: one-time payment, and you're good to go.
How much to spend? Balance the cost against the likely income to get an answer for that. Remember, most first novels sell 200 copies or fewer.
Hmm...How about an art piece instead?
Again, if you can draw or paint it yourself and make it look good, go for it. If you have an artist friend who will give you a sketch for use, hey, if it looks good, use it. If you want to pay someone...well, that's up to you again.
Use your art program (Photoshop or the like) to create a cover that has balance and punch. don't just stick the photo there, but find a composition that's striking.
Place your title and your by-line on the cover in LARGE, easily-readable type in a color that stands out. Remember, your browsing reader is probably first going to see the cover as a thumbnail, a 1.25x2 inch image (ore thereabout). It's important to give the potential customer a readable title, even that small.
Try to be sure that your cover is appropriate to the content. In the Jim Dallas series, I don't go for portrait covers, but for atmospheric ones that show or suggest some element of story, but there are all types of art and approaches. You can go abstract, postmodern, funky, impressionist, classic...your call again.
But remember, despite what everyone says, most people do judge a book by its cover, at least on first impression. Make a good first impression, and you're more likely to make a sale.