Get your printer ink cartridges refilled instead of buying new ones. It’s cheaper and saves on packaging and material costs.
Use both sides of the paper when printing. There are many ways to save paper and ink in the office. Also, if your print dialog box doesn’t give you the option to print duplex, you may find third-party software that will help.
Save your receipts to use as scrap paper. They make great grocery lists or art projects!