Pages
How do i get it back free 'cos apparently, you have to pay $19.99 if you download from itunes. If i cant get it back then how do i revert back to Mavericks?
MacBook Pro, OS X Yosemite (10.10)
Apple only keeps the most recent release of Pages for Mac in the OS X (not iTunes) App Store. Currently, that is version 6, and it requires macOS Sierra. All prior releases of Pages are no longer available from Apple.
If you do not have a backup of a Yosemite compatible Pages v5.5 through v5.6.2, then you are done with Pages for Mac on Yosemite. If you never downloaded Mavericks from the OS X App Store prior to the release of Yosemite, or your Mac shipped with Yosemite, then Mavericks would not be available to you via the OS X App Store, or other Apple sources, for installation on your MacBook Pro.
If you are jammed up and have no access to Pages v5+, then use Pages for iCloud to convert your existing Pages v5 documents to Word .docx, and install the free LibreOffice Suite, or use these .docx with Google Docs. LibreOffice is a true MS Office replacement suite, and far improved features, better Word compatibility than Pages v5/v6 exist in LibreOffice Writer.