simple iPad/iPhone reader

I need a very simple iPad/iPhone app that will display content in pages, allow the user to page forward and back, go to the beginning of the story and to any numbered chapter, and will allow in-app purchase of the stories. The content would be supplied as pdf files or individual images, whichever suits the app design better. A story runs anywhere from about 12 pages through to 100 or so pages. I will mark up the pdf in any way that is required (marks, filenames, whatever).