That is a great question! Please see below for the explanation of all three.
OEM stands for original equipment manufacturer. These are the expensive brand name ones that you buy at the store. Like the ones made by HP.
Compatible cartridges are just the generic (less expensive) version of the OEM cartridge. It is a 100% brand new product. Often times because of patent laws they can look structurally different than an OEM.
Remanufactured ink cartridges are essentially a recycled cartridge. Typically these have 85% new parts. They are filled with the same ink formulation, inspected for any possible leakage and tested to ensure they meet the printer manufacturer standards.
Answered on 10/24/2014 by Shoshana