I bought a Brother Toner cartridge for 12 quid for doing Black and white documents.
https://www.amazon.co.uk/gp/product/B079DVF7MR/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
If kids want colour or do photos it can get dearer.
I have my printer + an old scanner printer with dried up...