he probably wants to mine scrypt...
Yes, scrypt. According to my calculations, USB miners will never ROI.
at $8 each as you can buy them now on fire sale on ebay they ROI in 3 to 6 month. Reason? Although the hash rate will continue to go up like crazy in percentage will lower into the single digits per month, plus november and in particular december are going to be very slow in regards to hash rate increase. On the other end, unless you have free power you will never make ROI on a GPU, plus most ALT coins are already dead