As little as $25 will buy you access to a thousand malware-infected PCs, neatly packaged as a botnet army to control or spy on. That's according to a security researcher studying underground souks of zombie computers.

But the prices increase steeply for the more discerning crook who only wants to use compromised machines in America or Europe for nefarious purposes.

Whereas 1,000 PCs whose whereabouts aren't known cost 25 bucks, control over confirmed EU-located systems sells on one underground bazaar for $50, $225, and $400 for 1,000, 5,000, and 10,000 compromised hosts, respectively.

Botnets with drones solely located in Canada, Germany and Great Britain cost $80 per 1,000. Prices for top-of-the-line US machines start at 1,000 zombies for $120. By contrast machines located nowhere specifically cost almost five times less.

The figures were put together Dancho Danchev of security biz Webroot from sales prices advertised on a newly established underground cybercrime forum. US machines are more expensive because their owners have greater online purchasing power than their counterparts elsewhere, Danchev explained in a blog post.

Payment for the botnets can be made with various forms of electronic currency including WebMoney, Liberty Reserve and bitcoins.

The e-shop is another example of how hackers have adopted tactics from legitimate businesses, in this case market segmentation, to increase sales. ®