An idea to make money online is to create an E-book inspired from your blog or site.
If you have good unique contents, this could be an excellent way to generate extra income selling an E-book.
Probably the easiest way is if you have a good unique niche content.
You can collect some or the best of your articles, then report them in an eBook.
It is really easy to write an electronic book : write in Word and then convert it in PDF files, that is the most common and popular format.
Here you have some tips and suggestions that will help you to understand if you can realize this idea :
1) find the most popular categories to check what people are searching when they actually visit your blog (a good help is from the free tool Google Analytics or Google Webmaster Tools);
2) if you have enough popular posts coming in an unique category, you have already enough content to create your own Ebook;
3) in alternative, look for different categories that can match and organize the content in the chapters of your eBook.
Probably you can sell a 150/200 pages eBook for 20/30 dollars or more and if you have less than 100 pages you might think to sell it for a low value :
first check if you have a really good contents, probably you can realize a good income !
An easy way to get printed your eBook inspired from your blog is Blog2Print : you can choose the cover, the posts, the images and the contents you want to include and you are on your way to create your own Blog Book!
A nice tip to consider is to research what is popular online at this moment and you can do this, for istance with Google.com/trends , that will show you the n. 10 hot searches.
Even better, you should look for the trends that are willing to emerge in the near future.
You can also use another free tool from Google to search for popular keywords to get an idea for your niche : Google Keyword Tool.
Once you created a good content eBook, prepare to advertise it trough a marketing campaign and do not forget that affiliate programs can help you !
Good luck !