Which is the best way to cut down your printing cost refilling the old one or buy a new compatible cartridge?

Both the ways could be good for you. Both are extensively used by those, who are looking for cheaper printing solutions. Think you are a new printer user, and have never used one before! Anyways, I'm gonna shoot the light on you about both the printing alternatives.

Refilling -> Refilling is the cheapest printing option one can get. There are some third party manufacturers, producing ink refill kits. Refill kits have ink that can be poured into the cartridges that have gone empty. The quality of the inks may vary with the standards and techniques, followed by manufacturers. You will have to find the best local brand, if you are going to use refill ink kits.

To buy refill kits, you have to follow the same procedure, which you go after, when you buy original cartridges for your printer. For an instance - as you said, you're looking for HP C5011AN, then you'll have to find refill ink that is fit for this series. Investing into anything otherwise might not give desired printing results.

Some people find using refill kits a great mess. But if one is following the step-by-step process, as advised by the user manual, given with the refill ink's package, it won't be a mess any longer. Refill kits come with ink-bottles and needles; however, there are some manufacturers who prepare bottles, having needle like tap, which works as a needle, at the time of refilling. To fill the ink, you need to plug out the cartridges from your printer, and locate the puncture on the cartridge, through which, the can ink can be injected with the help of the needle and syringe. Do not forget to keep a dusting cloth with you, when refilling your cartridges. Remember, it is the cheapest printing solution - you can save about 80% percent of your yearly printer expenses, by using refill kits.

Compatible cartridges -> Compatible cartridges also provide you with low-cost printing solutions, up to 50-70% lower rates. These are third-party-manufactured cartridges that are sold at very low, attractive prices. Once again, you need to be a bit careful; there are so many intermediary brands with different qualities and standards; you may have to strive hard to seek out the best out of them.

You must buy the compatible cartridge for your printer model that is suitable to work with your printer. This is a precautionary suggestion, which you must follow, to avoid any hardware damages.

Out of these two, refill ink is the cheaper utility, but if you are looking for less messy option, compatible cartridges. AtlanticInkjet.com, 123Inkjets.com, 4inkjet.com are a few names that you can trust, if you are going with either of these two options.