Yes you can sell your ebooks online at no cost to you. This service is available at Lulu.com. All you need to do is save your manuscript as a PDF file and upload it after having registered for free at the site. You determine the selling price of your ebook, with Lulu getting a small percentage from each sale. Once your share of sales has reached a minimum of $5, they send it to your PayPal account.
Writers and artists are selling all sorts of ebooks at Lulu. There are novels, anthologies and even single short stories. There are biographies and how-to books, as well as cookbooks. There are graphic novels and collections of photographs or paintings.
If you don't have your own ebook material right now, you can always buy one that comes with full resale rights. An example is My Google Money. For only $9 you own the right to resell the ebook at any price and keep all sales as pure profit.
Some of my romance novels in Filipino are for sale as ebooks at Lulu. Do check them out! :-D
Let me know when your ebooks are up, too. Good luck!