Most of you probably aren't looking to buy a cover for something you haven't written yet. For the sake of creativity and inspiration for those forthcoming 50K+ words, why not create one yourself? Here are a few tips I'd like to share about creating a book cover to use on the NaNoWriMo website.
1. Images. I know this cover is just for fun, but I'd strongly suggest you not use images you found somewhere on the internet. Even though you're not using the book cover for commercial purposes, you're putting an unauthorized, edited version of the image online—and the original artist or photographer might not take kindly to what you've done with their work. Consider using a plain background, a photo you took, a photo from a copyright-free site (which is still not without risk), or a photo that you do have permission to modify for personal use. I know this may limit your options, but copyright infringement is a can of worms you really don't want to open.
2. Text. In this case, it's acceptable to download and use free fonts listed either as "personal use only" (and of course "OK for Commercial Use") because you will not profit from their usage in any way and you're not modifying the fonts themselves. Choose fonts and colors that are easy to read at thumbnail size for both your title and name. (I'd avoid using red on black in particular—it's aggravating to read. Go for high contrast!) Don't cover up the focal point of your cover art; similarly, don't hide your text at the very top or bottom edge of the cover or place it in an area with a complicated/"busy" background. Avoid stretching words to fill empty space as well.
Ex: Simplicity is good, mmkay?
I've created a couple of image files to help you design your NaNoWriMo book cover. The first is a gray 230x300px JPG file, as those are the dimensions specified for book covers on the NaNoWriMo website. To use this, simply save it to your desktop and build your design over it your editing program of choice. If the required cover's odd width irks you, skip this: I have a workaround of sorts that will allow you to display your cover at a more 'typical' size.
Import your book cover and stretch it over the gray area of the PNG, leaving the transparent area clear. Once you've done this, save the file and upload it to the NaNoWriMo website.
If you want your book cover to be centered rather than offset to the left, use this PNG file instead.
It looks wonky, but it shouldn't be a problem—this module will only show up on your personal dashboard.
Please share your covers with me—I'd love to see them!