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. If you want to print 'photo-quality' expect to pay slightly more. This is only applicable if you are doing business printing and need to print on carbon or carbon-less multipart forms. Printing on these forms requires a dot-matrix impact printer. Laser and ink-jet printers also have limits on paper thickness.