Note that my site has Project Wonderful!
That means if you have something -- an ebook (or physical book), an Etsy site, a webcomic, whatever -- that you'd like to advertise, you can do so on my site (probably very cheap!) on Project Wonderful.
I've used Project Wonderful myself and been able to advertise on many different websites for very small amounts of money (i.e., my ad budget total was $100, and I got many months of use out of that). Currently there are NO bids in the US and Canada regions and only a few in the other two.
There's a total of five ad boxes -- one half-banner near the top of the page, and four square boxes towards the bottom.