Sadly after doing the "Math" you will find that inkjets using high quality
3rd party ink is a lot cheaper.
Black and White Lasers can be bought for $80 and the print quality is
excellent but those 1500 and 4500 page toner carts are expensive, $75 for
the 1500 and $130 for the 4500 page cart.
Let's imagine you actually get 1500 pages out of the $75 cart that works out
to 5 cents a page and about 3 cents a page for the 4500 cart.
The problem is you will only get half the page count, so double the numbers
above.
Lasers can print 5000 pages or more per month and not wear out.
Inkjet:
Inkjets don't cost much either, right now the Canon IP4000 can be bought for
$50 after rebate. The pigment black is excellent and waterproof. The text is
sharp and nearly laser quality. Refilling it with bulk ink from
http://www.alotofthings.com/catalog/bulkinks_Canon_BCI-6-BCI-3.htm will run
you about $1.35 per cart. The cart can do about 500 pages real world. So
1500 pages would cost you $1.35 x 3 = $4.05. That is a lot cheaper then $75
per cart for the laser.
The only downside to inkjet is the monthly duty cycle, they are usually
intended for Home or small office use. A friend owned a i860 and printed 600
pages of text per month as well as photos and DVD covers. After 2 years of
heavy use the printer was worn out. Not a big deal though he just bought the
IP4000 which uses the same printhead and carts.