I recently purchased 4 XL sized cartridges (black, cyan, magenta, yellow). They came in one order but I bought them individually as it was slightly cheaper than getting them as a set bundle/combo pack.
I've never had a problem with HP inks bought from Amazon. Getting them from Amazon means they are usually cheaper than other suppliers but they are still very expensive and, frankly, a bit of a rip off.
Until recently it was not possible to get chipped HP364 compatibles but I notice these are now becoming available (even on Amazon). I'm going to try one soon to see if my HP printer will let me use them and, if it does, how they compare quality-wise.