This is a PDF editor (Windows only) that can be used to edit, annotate, sign, create fillable forms, import/export, etc.
Version with OCR also available for US$10 more.
If you just need basic split/merge/rotate functions a free version is available - https://pdfsam.org/pdfsam-basic/
Review: http://www.top10pdfreviews.com/pdfsam/
Given the title I would expect this deal to be available until at least 22/11/18.
P.S. Thanks to jace88 for the lead.
How weird is this.
I go to YouTube to look up videos on PDF Sam and see a video of Jimmy Kimmel where Doc Brown and Marty travel to 2015 (great segment!). Then come back here and realise your username is McFly.
Maybe it's not so weird and can be explained by cookies and Google.