I don't know if this is what they purchased, but EcoTank is a good term to search for if you want an inkjet that won't charge you an arm and a leg for proprieta

I don't know if this is what they purchased, but EcoTank is a good term to search for if you want an inkjet that won't charge you an arm and a leg for proprietary cartridges. The basic idea is that instead of swappable cartridges, they just have ink tanks that you top up from a squirt bottle. These bottles are cheaper than any cartridge while containing like ten times the amount of ink.