I bought iPrint Refilling Kit from Big Lots!. Black sells for $8 and the Color one for $12. The kit and the ink work just great. I have a unique way to unclog an HP Cartridge, which may work for other brands too, using Washing Machine's Spin Cycle. See the Posts on Unclog.
Unclogging an HP Injet Cartridge:
After filling in the ink the usual kit way, I could not print anything. I tried all the usual cleaning methods without success. I happened to read on Google Search that perhaps there could be air bubbles trapped inside. I figured a way to get the air bubbles out...