Split a PDF in colored and b/w parts to optimize your printing expenditure. Code written in 5 minutes, don't sue me if you pay more than what it estimated.
sudo apt install ghostscript
sudo apt install pdftk
Uses a default python version installed in /usr/bin/. Change the first line (hashbang) for your python version if 3.6.8 is not present.
./splitpdf /path/to/file.pdf [-n]
-n option will only give total counts and page numbers. On not using this option the PDFs will be dumped to current directory.