Finding ebooks on "the cheap"
"The Cheap" is another source of free or low cost offerings from Amazon, Nook (Kobo) and Apple. The titles change frequently so be sure to check in often. Always double-check the price on the seller site before downloading as some offers are time limited. You'll find a range of "official" and self-published works here. (Note: While the link above brings up kids' books, there are also other categories available by browsing the site, so I would suggest sharing the availability of a particular title with kids, but not the whole site!)