Pssst, buddy: Got a kidney you wanna hock?

Spammers will try anything to get users to reply to their email pitches, including offers to buy body parts.

"Sell your organs online!" touts the subject header that spam receipts will find in their inbox. And in the message, it reads: "Please reply to this email if you want to make some cash selling your organs!," according to a warning issued Wednesday by SophosLabs.

In the world of supply and demand, it seems these spammers would find more interest among fellow organ buyers than sellers. But in the spam world, it's not a simple case of Econ. 101.

"This sort of spam should focus the mind on how the spam economy works," Paul Ducklin, Sophos head of technology, said in the advisory. "A handful of responses - one or two, even - would represent success to the spammers, because their operating costs are borne by you and me."

Sophos advises users to forge giving these spammers your organs and instead offer a cold shoulder.