Although various color combinations and processing variations have emerged over the years, the basic concept of an anaglyph is largely unchanged since the 1850s. Nearly all methods start by capture of a stereo pair of images which are then manipulated to create the anaglyph. In contrast, the method discussed here involves modifying a digital still or video camera to directly capture a high-quality anaglyph in a single shot -- with no post-processing needed.
Did I mention that the reversible modification to your camera can cost less than $1?
Step 1: What You Need
1. The camera and lens to be modified
2. Two pairs of identical paper anaglyph viewing glasses
3. A method of mounting (paper, tape, and scissors; optionally, a lenscap and drill)
This method works with most cameras and lenses, but works much better with some than with others and is a little touchy about some details. Don't be scared by the large number of steps in this instructable -- that's just trying to make sure that you get things working as well as possible without a trial-and-error process. This is easy.
Cost? Well, you probably have most of the stuff you need. The paper anaglyph viewing glasses are widely available for free in small quantities. I've bought hundreds at an average cost of $0.32 each including shipping, which would bring the "new purchase" cost to $0.64 for the two needed... easily under $1. Using a lenscap instead of paper printout for mounting adds about $1 to the cost, but yields a "more professional looking" and more durable device.
Note that the post processing described in steps 12, 13, and 14 is optional. You don't need a computer to make anaglyphs by the method described here.