Ask for advice in your local computer store who are not commission based.
Find a good printer deal and check the price of cartridges.
Check how many pages a cartridge is quoted as doing.
Read user reviews online.
Consider different brands.
Choose a printer that will accept compatible cartridges, which will generally make it allot cheaper to run.
Think what you normally print, do you need to print just a few pages or dozens of pages a week?
Buy a printer because it is on sale or because it is cheap.
Blindly follow in-store recommendations from commission-based salespeople.
Assume cheap cartridges are better value.
And Lastly Before You Buy
Ask yourself do you need any of the following features.
AirPrint - Print directly to your printer from a smart phone or tablet.
Card Reader - If you use digital cameras or other card-devices a lot, a built-in card reader slot saves a lot of time.
Duplex - Printing onto both sides of the page automatically, a great money-saver if your home printer does a lot of work documents.
ePrint - You can email your printer documents and it will automatically print them, perfect for leaving things ready for you at home.