Go to their page and just scroll down. For a long time. Take screen shots and save them.

That only works if their page is public, or you're their friend. :)

• get the "Go Full Page" Chrome extension (this eliminates the need to scroll and screenshot multiple times) https://chrome.google.com/webstore/detail/gofullpage-full-page-scre/fdpohaocaechififmbbbbbknoalclacl

• scroll all the way to the end of a users posts (if they lazy load as you scroll)

• click on the Go Full Page icon (it will capture everything from the top down as one image)

• save as .pdf, image, etc.

Friend the person and start scrolling down.