If you're looking for an affordable, economical inkjet printer, I strongly recommend Epson.
They have the largest product base of consumer 3rd party continuous ink supply systems (CISS) and refillable / re-usable ink cartridges. You'll find many of these 3rd party products on eBay and online stores specialising in printer ink supplies.
For example, at home we have an Epson Stylus Photo R220 printer. Instead of using original single use cartridges (or 3rd party ones for that matter), we've installed a continuous ink system (where ink cartridges are fed via tubing connected to external ink tanks placed beside the printer). It does take time to install, but once that's done, and assuming you maintain and use the system properly, all you need to do is top up the external tanks with ink. The cartridges reset themselves.
At University, I have an Epson Stylus DX5050 all in one printer, and do loads of printing. While continuous ink systems are available for my printer, I use 3rd party refillable / re-usable ink cartridges instead, as the initial price is cheaper, and it makes the printer easier to set up and transport. In a way, it's similar to a continuous ink system in respect of the refillable cartridges, but minus the external ink tanks and tubing connecting the two together - the cartridges themselves are refilled directly, rather than being fed via external tanks. The cartridges reset themselves, just like a CISS, and all I need to do is refill them with inks which can be cheaply purchased online.
Both a CISS and standalone refillable / re-usable cartridges (compared to original and 3rd party single use cartridges) are cheaper in the long run, last longer in terms of ink capacity, can hold more ink, do not need to be refilled so frequently and are more environmentally friendly since they produce less waste. With my Epson DX5050 printer, I'm inconvenienced more due to running out of paper and having to go out to buy more paper, than due low ink levels!
Inkjet printers aside, If you do mammoth amounts of printing, then maybe you should consider a laser printer. They're becoming more affordable for consumers these days.