Telephone Call Mystery Shopping Assignment are great if you are looking to make some extra money and you don't have the time or you want to travel to do mystery shopping assignments.
They generally don't pay as much as a walk in assignment but they are generally quick and easy.
Normally you are given a scenario to follow and you either make or receive a call from the mystery shopping target. You should expect to get anywhere between $6 and $15 per call and generally speaking you will get a few phone calls per assignment.
I have done many telephone mystery shopping assignments with Australian Quality Monitors on businesses such as including medical, utilities adn insurance. The assignments are easy to complete and in the most recent job I did 3 x 10 minutes calls and received $37 for my efforts.
Other market research companies that I have done telephone (and email) assignments for are Hoed, Retail Mystery Shopping Australia and Shop Angels.