Color laser printers are considerably cheaper than ink jet. I have a Brother color laser and the toners only have to be replaced every year or so, and my wife prints a fair amount on it... in part because she was replacing the ink cartridges in her printer every 2 - 3 months (at $60 ea.) while the laser toner is around $80 - $90 but they last 5x as long.
Decal-wise, every ink jet decal paper I've used is crap compared to the higher quality, thinner (and "real") decal paper that can be used in a laser printer or a dye sub printer like the ALPS (Oki used to make a dye sub printer as well).
If you want to print white, the easiest option is an Oki /ALPS 5000 off of ebay. The ALPS printer is a delicate, ornery princess. If it weren't the easiest method of printing white, it would have gone through this "Office Space" experience:
With some effort, you can print white and full color decals on a regular color laser printer.
Pulsar Pro fx (
http://www.pulsarprofx.com/) has their
Decal Pro method that produces full color rub on transfer decals (or water slide, if you modify the process slightly). It is a lot more involved, but cheaper than the Oki printer.