The cheapest source of toner cartridges may be Office Supply Outfitters. As a comparison, black toner for the HP Laserjet 5000 costs only $50, while an equivalent product sells for over $200 at Staples.
It is quite hard to find good, cheap printer toner. I would check Office Depot as they have the largest selection and you are guaranteed to find that one that you are looking for. They generally carry the larger brands, but it is worth it.
One can find generic color toner cartridges online on websites, such as Amazon, eBay and Best Buy. Generic color toner cartridges are available for different printer types.
There are many places where one might find HP 15A toner cartridges for sale. One might find HP 15A toner cartridges for sale at popular on the web sources such as the official HP website, Amazon, and eBay.
One can find replacement xerox toner cartridges online at sites such as Ebay and Amazon. One could also order these types of items from the Walmart online shopping site.
There are a lot of refiled toner on ebay or amazon maybe for the HP 15x too. I am sure one can find cheap HP 15x toner there or on special toner shops offline and online.
Any company that sells printers will provide the opportunity to purchase toner cartridges. http://www.tonercartridgedepot.com/ is a good resource for finding the best options.
Remanufactured toner cartridges are sold by 4inkjets, Ink Technologies, Ink Grabber, Staples, Overstock, Cartridge World, ClickInks, TonerPirate, and eBay.
One can buy Dell toner cartridges from Staples, Walmart or Target. One can also purchase Dell toner cartridges from online sites like eBay or Amazon as well.
One can purchase cheap HP laser toner cartridges at several retailers including Office Max, Staples, Office Depot, and Amazon. Staples also gives $2 back per recycled ink or toner cartridge.
One place to find cheap toner for the HP 4200 is from HP directly. Another good place is clickinks, they usually have a good coupon towards ink and toner.
Brother TN580 cartridges are carried in major retail supply stores like Staples and Office Depot. If one takes advantage of advertised sales at these retailers, one can purchase these cartridges at a discount. Otherwise, one can check websites such as Go4Supply, Dura-Toner, and CartridgeHub for savings on this item.
One can purchase OKI Toner Cartridges from many stores and websites. For instance, OKI Toner Cartridges can be purchased from Amazon, Office Max, Office Depot, and the official OKI website.