When you are done with your PC and want to go out in the real world (which we should do more often), do not just power off the printer abruptly, but press its power button instead. Inkjet printers usually park their cartridges against a rubber cap when turned off, so they do not dry up. If you just cut off the power, the printer cannot park properly.
( photo above: ink cartridges inside their compartment )
Sidestep the Warning
Do not change cartridges at the first warning from the printer. A low ink warning means you can do some more prints. Wait for the printout to really show loss of quality before calling us for new ink.
View the Preview
If your printer driver has a preview feature, do use it before printing web pages. Web content are not usually formatted to fit on one page, and many sheets tend to be wasted while trying to print just a part of a web page.