Really depends on the service. If you think of a laptop/phone tracking service as a productivity/accountability tool for businesses to keep an eye on their workers it only has to save 2 hours of productivity in a month to pay for itself even if you're deploying it for minimum wage workers. (unlikely) If the service is too inexpensive they have more users to support and many of them may decide that even $2-$3/month is too expensive if they don't have any good reason to be using the service in the first place. If they keep the price high they attract fewer but higher quality customers that are cheaper to support. I'm guessing many of these services do offer good volume discounts.
