How to Block Phone Calls for Free

1. Register with the National Do Not Call Registry. Once you are registered, telemarketers must stop calling you.
2. Block the calls through your cellphone. Some phones allow users to block calls from unwanted numbers. Consult your phone's manual or your cellular service provider, or search the Internet to find out whether your phone is capable of blocking calls, and how to block them. Applications for smartphones let users block calls as well. If you have a smartphone, check your phone's marketplace for a free application.
3. Contact your phone service provider. Some cellular and landline telephone providers allow you to block calls from certain numbers for free. The availability of the service and the number of phone numbers you can block vary by service provider.
4. Attach an inbound-call blocker to your landline phone. This is a device that requires inbound callers to enter a special code before their call will ring through on your line. You will receive calls only from those you have given your code.