Co-op Mailing (short for co-operative) means that two or more businesses
share in the cost and distribution of a direct mail campaign. It's kind of
like having you and another non-competing business split the cost of
printing, assembling and mailing an advertising flyer to a shared (same)
market base.

Co-op dealing is very beneficial (and usually safe) for everyone involved.
One example of co-op dealing in mail order is to send your 8 1/2x11 camera-
ready circular to a co-op printer and they'll print your ad on one side,
their ad on the back side and ship them back to you for a low cost of around
$10 per 1,000. You get your printing almost free and the other dealer gets
his or her flayers mailed on the back of yours free.

But what do you do with them when they are mailed back to you? If you're new
to mail order it's doubtful you have a mailing list to distribute them to.
Plus, postage costs alone would run you about $290.00 first-class. At this
rate it would have been cheaper to send the camera-ready to a tabloid or
ad sheet publisher rather than by a co-op. But don't despair.