Multi-Task Switch or Blinker Relay?

I own a 2000 Pontiac Grand Am SE. The turn signals work perfectly. However, after using them, or occassionaly driving down the highway, I hear the same "clicking" noise as if they were being used. I have been told by a few people that this is the cause of the Multi-Task Switch, and I have also been told that it is the blinker-relay. Which is it, and how do I replace it? Is it costly? Thanks.