What are "ashcans"? What are their purpose? Where does the name come from?
(This is all based on reading about ashcans on a variety of indie RPG sites a year or two ago. I have purchased a few.)
The word "ashcan" comes from the comic book industry. In recent usage in the comic book industry it tends to mean a smaller format comic (for varying meanings of "smaller") used as a freebie to try and hook new readers.
In the indie RPG scene, an ashcan is a sort of pre-release, a weird sort of public beta-test. A designer might not feel their game is done or has uncertainty. The designer wants feedback from a wider group of people. This would normally be done by playtesting, but: the designer may have exhausted his playtesting pool, the designer may want opinions from "normal" gamers who wouldn't normally engage in playtesting.
Generally speaking an ashcan looks "finished," frequently with production quality comparable to the final product.
By and large you pay for an ashcan RPGs. While this limits your player base, the people who purchase it will almost certainly be more invested. The problem with, say, a free online release is that you'll get lots of downloads from people who will never play it. They might offer feedback, but the designer wants feedback from actual play, not feedback based on just reading the rules. If you've spent a few bucks on the game, you're presumably genuinely interested. You're more likely to seek out a group, to try it repeatedly, and to be interested in providing serious feedback.
Finally, many ashcans come with a discount on the final game as a sort of thank you.
According to this:
And According to wikipedia:
According to this blog's usage:
Therefore, an ashcan release is one done as an initial, unpolished release designed to satisfy certain IP elements and, if sold at conventions, serve in many ways as a paid-for alpha test. A synonym would be "pre-release edition." The important aspect is that it is legally published, but not designed for wide consumption. The name comes from, as per wikipedia, the comics publishing industry.
There also is/was a group called the Ashcan Front, that is/was using the medium in a very particular way as part of the roleplaying game development process. I think it is sort of dormant now but I don't really know. Anyway, that's a link to their FAQ.
The notion was that only people invested in a project would actually buy an ashcan, which is expressly unfinished and in development and full of questions, and that they would become part of a playtesting conversation that would improve the finished game.
In games prior to the 1990's revolution in publishing technologies, it usually meant a self-published version intended to be used to shop it around at cons to both a select group of playtesters, and to the big companies in hope of a "real release." It also would have two copies sent to the Library of Congress to establish formal copyright protections.
Some ashcan versions were near-professional layout quality, others simply optically typeset text, and were not in distribution networks. Several games mention shopping around the ashcans prior to being sold to a major company.
Given that many printing houses in those days required a minimum order of at least a hundred copies for a bound volume of any kind, it was common for such versions to be sold via mail, convention, or personal contact.
The term was often synonymous in use with "low quality cheap printing", as many were printed on the cheapest set of options the printing house would allow. The few examples I've seen of this mode were hand-typed mimeograph master dittoed (run off) on recycled unbleached high-acid newsprint, and used for playtest.