[Free X+]

Depending on what type of setup your running you may be able to access the files on the slaves's computers (I know this can be done in DarkComet and other generic rip-offs) and modify the DNS server that they are connected to. From there you can pretty much do what you want, like make a DNS server that reroutes all money sites like PayPal or MoneyBooker to a phishing site that makes every purchase transferred to you instead.

^Which imo is safer than carding or spending time with redirecting them to referral sites.