Cold calling is practice of randomly calling people and then trying to sell them your product/service. The success rate of cold calling is very low but majorly the purpose of cold calling is to remove the impossible buyers from your list of prospective consumers so as to have better and more efficient communication for the remaining ones.
Dialing for dollars is similar to cold calling, the difference being that dialing for dollars is seen as trying to sell something fraudulent over the phone like a penny stock.
Dialing for dollars was also a popular television show in US and Canada from 1950s to 70s where the host would announce a password on the show and then randomly call people. IF those were able to answer with the right password, they would get monetary prize for it.