I have personally purchased from this website, this is a company established in New Brunswick - What I purchased from them are the EMPTY, easier to refill carts for my EPSON, I don't know if they have those for HP. Now I have an EPSON R200 and one HP DeskJet 712C that is still kicking Now my EPSON R200, I refill using the EMPTY carts from re-ink, however the refill ink I use is made by JETTEC, it is the 5 colour refill kit, after using many other inks, I find the JETTECs are the best. I have used inks from different places, including Q-Inks that claim to be quality ink, and found that most 3rd party inks are poorly formulated (either fade out very quickly or they are not colour accurate and while you will probably not notice for printing text and some graphics you WILL notice when printing CDs and PHOTOS......Which is why I use the Jet Tec inks, so far I find that they are a very close match.
Now about re-inks, the empty carts I got from them are much easier to refill, from the top, however, the sealing rubber cap is a major annoyance to get out, often breaking it along the process, then there is one cart where the valve doesn't function I have to plug the outlet hole...... All in all refill have worked fine on my printer and saved me $$$$ but they are a major annoyance. (air bubbles is often a problem) at times I have to engage in cleaning cycles to get those nozzles clear.
If you are willing to pay a bit more for peace of mind I recommend the Jettec cartridges, which already have JETTEC quality inks in them - I have used those and they worked fine - Only thing is that my EPSON likes to engage in cleaning cycles when it decides, and very often, for no bloody reason.
About HP, unlike EPSON, the heads are on the cartridge itself, so I usually would not recommend refilling those as with time the heads will wear out, so in the HP case you would get the already filled cartridges.