ink cartriges

well for those who dont know i collect used ink cartriges from all over the place and turn them in for 3 bucks each at staples well to add an update to this so far to date i have turned in 107 for 321 bucks now i can only use 9 bucks at a time but i have bought pens and pencils and stuff and when i get enough built up i will sell it on ebay