How do you know if your phone has been tapped without having to buy expensive spyware devices?

First as the questions has anyone had access to your phone? Is there a reason for them to tap you? Is there something that needs to be kept secret? To guard against unofficial line taps, the phone should be regularly inspected, and the telephone line should be checked for new joints, or small wires connected to the line; a time-domain reflectometer is a good tool that could help you (too much for to explain in these answers but you can google it) The best thing to do if you think your being tapped is contact a technical surveillance countermeasures (TSCM) specialist. But dont contact them from the infected phone, a company phone, a cellular phone or ANY personal phone of yours. Do it from a payphone or phone of a nonimportant 3rd party. They’ll let you know for sure.