What do you buy?
Is there a difference in quality?
How much cheaper are generic/compatible ink cartridges?

Genuine Cartridges 

HP Genuine ink cartridge


Industry terms are Original, OEM, Genuine

Genuine ink cartridges are made by your printer manufacturer or they pay a licensed third party to make them on their behalf.  Genuine ink cartridges will provide the most trouble free result for printing.  You will pay more for using the genuine products over the compatible inks and toners. While genuine cartridges are more reliable than compatible products, even they do have times where the cartridge fails for one reason or another.

Compatible
Industry terms are Generic, Non-Original, Non-Genuine

A compatible ink cartridge is a new cartridge that has not been refilled or remanufactured.  It has been manufactured by a third party ie that is not the original manufacturer.
Generic or compatible cartridges are alternatives to the genuine branded product, they are in usually the cheaper option for the consumer wanting to save money on their printing costs.  Generic/compatible cartridges will in most cases contain the same amount of ink or toner so to produce the same number of pages as you would get from a genuine cartridge.  Therefore comparisons are easy to make simply according to the price differentiation.  As with most products there are different levels of products available so customers need to choose carefully with their selection and the brand.  Compatible cartridges are sold with a 100% satisfaction guarantee. Some manufacturers will tell you that they will void warranties but the department of Fair Trading has made rulings that will not support that theory.

 

Remanufactured

Industry Term: Reman, Remanufactured

Save money on generic cartridges

Remanufactured cartridges are used original or genuine cartridges, which has been either refilled, cleaned, tested and new parts fitted by a manufacturer that specialises in this procedure. Remanufacturing is done where copyrights may be contravened if compatibles are produced or the volume of the original cartridges may have been too small to produce a compatible range.  Remanufactured cartridges are usually cheaper than new genuine cartridges and performance should be the same as a compatible cartridge. Like all cartridges they are sold with a satisfaction guarantee.

Tonerink refer to all remanufactured cartridges as compatible or generic for simplicity.

For whatever cartridge you choose there is usually an alternative which will provide cost savings over the original.  The ultimate decision must be yours dependent upon how you perceive the product.