Ink-jets can be purchased for low cost, but the supplies can quickly eat up any savings. Laser printers are more expensive and their toner cartridges cost more than a set of ink-jet cartridges but they will produce many more pages. Laser printers deliver the lowest cost per printed page of any output device. Producing one set of 30 color overhead transparencies can consume the ink. Costs of operation vary widely and depend on what type of printing you do.
Standard text is least expensive.
High density graphics in color is most expensive. Paper costs need to also be considered. Most ink-jets can print acceptably on standard bond paper, but their highest quality settings will require special coated paper which is expensive. Laser printers run well with standard bond paper that is acceptable for copy machines. If so, ink-jets are the most economical solution.