Remember that psychological services may be merchandised as well. Keep the source in mind when reading the claims of makers of home biofeedback machines, sleep-learning devices, subliminal CDs, and the like. Be wary of expensive courses that promise instant mental health and happiness, increased efficiency, memory, extrasensory perception (ESP) or psychic ability, control of the unconscious mind, an end to smoking, and so on. Usually they are promoted with a few testimonials and many unsupported claims (Lil-ienfeld, Ruscio, & Lynn, 2008).