You don't need to fake sales. Has anyone been in a public library recently and seen 4 or 5 copies of Obama's biography or the multiple copies of 'my little transgender pony' or the other shit in there. Obviously, most titles in the fiction section are what is popular but anything to do with social sciences is easy to pad using the public library system.
http://www.ala.org/news/state-americas-libraries-report-2017/executive-summary