There is no guarantee any store provides ebooks that look like the print book - while epub formatting allows a lot of precision, most publishers don't take advantage of it, and even those that do, it's a book-by-book decision. (Newer books may be formatted with all the correct fonts, layout options, etc.; older reprints may have just basic formatting.)
If you really, really want it to look like the print version, you'll have to look for PDFs, and as you've noticed, they're often not available. (And some stores don't bother to tell you even when they are available - they just say "Adobe Digital Editions" and don't mention whether that's epub or PDF.)
Next option is to get epubs and figure out enough of the coding/css options to run it through a conversion process that makes it look more like what you want to read. There's no simple solution for that, because most people who read ebooks want the reflow options, so that it fills whatever screen they're using at the time.
I'm fond of the
EPUBReader plugin for Firefox; I can open books in that and resize the screen to whatever's comfortable.
"Free flow" likely means epub, where the text matches your screen, like an HTML file. It doesn't mean no line breaks or no chapter breaks; it just means that your "page" is the viewer window.
"Original pages" sounds like a PDF, presumably a searchable version, with fixed page layouts - you see a whole page at a time, and if you shrink your viewing window (whether that's a browser or some version of Acrobat), you either get a smaller page that's hard to read, or a zoomed-in section so you'll have to scroll around to see everything.