From the comments, it seems that the phone number belongs to some telemarketers. Telemarketing cold-calls to cell phones (without a prior consent or prior business relationship) are forbidden by law (FTC regulation). Even if the telemarketing company is offshore (e.g. in India), the U.S. client company can still be fined. See the FTC website:
http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt107.shtm
which states:
32. Are telemarketing calls from overseas covered?
Yes. Any telemarketers calling U.S. consumers are covered, regardless of where they are calling from. If a company within the U.S. solicits sales through an overseas professional telemarketer, that U.S. company may be liable for any violations by the telemarketer. The FTC can initiate enforcement actions against such companies.
You should tell the telemarketer (if you can actually speak to someone) to take you off their call list, and if they do not comply you will report them to the FTC (at www.donotcall.gov), AND that you will also complain to their client company (e.g. the newspaper company that they are telemarketing subscriptions for) and tell their client company that they may be fined in an enforcement action.
Even if they are "giving away" a trial subscription, they are still telemarketing - if you (1) promise to cancel before the trial period is up, or (2) promise to pay for the renewal after the trial period, the promise is an obligation you are taking on (either way), and is an exchange of consideration. This exchange of consideration is payment for the trial subscription, thus this is "commerce" and is telemarketing.