If you really need to save money and still keep printing then I suggest that you refill your existing cartridges.
I have an HP F380 printer, bought in 2007 for £30, which takes the same cartridges as your F4180 (No. 21 Black and No. 22 Colour, both unchipped) and I have refilled the current black one for the last 3 years and the colour cartridge for the last 2 years. When you get used to it, it takes about 30 minutes to refill both cartridges and costs about £1.
To make them last such a long time, the trick is to refill them BEFORE they run out.
This stops the electrical heater element in the print head from burning out when it becomes empty and dry. I top up my cartridges every couple of months and the print quality is as good as it ever was.
Refill kits from ASDA are cheap enough and the web site below will help with instructions.
http://secure.stratitec.com/
Considering the money you could possibly save, it's well worth giving it a try.
I appreciate that your existing printer is a bit temperamental but maybe a re-installation would sort that out???