Most people who have a computer also own a printer (HP is a good brand), and if you are a regular printer user then you know that printer ink is not cheap. Shopping around can be time consuming if you want to save a little money buying a replacement, but there is an alternative to buying a new cartridge to use in your printer. It is recommend you have a look at thisyoutube video.
This video shows you how easy it is to do your own refills and how you can save more than a few bucks if you are an active printer user by filling the ink cartridges in your printer yourself, it really is easy.
The most important thing in this process is making sure you buy the correct or compatible ink for your cartridge you want to refill, in this video it shows the HP 78(c6578) as an example of how easy it is. It also makes sense refilling because by not throwing away the cartridge it eliminates waste as well.
Buying a refill kit is the best way to go, some people have experimented using a syringe and ink, just to find out later that the ink they used was not compatible and it clogged up their cartridge. In that case a person will have to buy a new ink cartridge anyway and the little experiment will have ended up costing them almost the same price of a new ink cartridge.