- you can sell the ebooks again - you can come up with your own minisite and you sell the ebook and at the same time, build your list - you can bundle the ebook with other digital products that you also have resell rights to
Advertise on free classified sites. Find relevent groups on social networks and advertise your links there. How about the local newspaper classified ads?
A nice innovative way is to createa facebook application to display what Ebooks you currently have available,allow comments and reviews of such ebooks. I think you can figure out the rest