a place for zinesters - writers and readers
It's true, cheap is relative... seems you'll have to toil away in an epic battle of quality vs quantity, especially in the arena of color.
Stankzine, I'm not sure where you are (Brazil, really?) in the world, but if you have access to big box stores, I second Dan's suggestion, although color copiers on the honor system are becoming more and more scarce. Alternately, depending on the scope of "cheap," I know some folks have had good luck with small, local printers doing the dirty work.
On that note, if anybody wants to pay to get their zines printed, I highly recommend 1984Printing in Oakland, CA. I'm not a spokesperson, nor have I had anything printed with them. Rather, everything I've seen printed by them has been top-notch, full color, B&W, and combinations of the two.
I haven't looked at a photocopier in a while but it may be that the newer machines automatically do it. But if they don't (or don't have the ability at all) I'd be willing to bet that the big copiers behind the counter can do it.
But I'm pretty sure there's still no good way to print high quality color photos for cheap...