If you expect someone to drive out to your house, wait for you to answer the door, put in the canisters, spend time in obligatory radon-related and non-related chit chat, then come back again later to take them away, wait at the door again, chit-chat again, then send them to a lab and pay the lab for whatever it does, and then call and/or write you after they get the results back, you got to pay for all that. They wouldn't do this if they couldn't make a living at it.
Who's to say if they should live like migrant farm labor or like Rockefeller or where in between?
The DIY version is not like making Chippendale furniture. You don't need to go to school or have years of apprenticeship. You open the package, read the instructions, and put what's inside somewhere. Then after the proper amount of time, you take it and mail it, probably to the same lab the local inspection company uses. I'll bet you they didn't say they did more than they actually do, but personal service costs money.
IIRC, I set my detector on the bottom horizontal part of the I-beam that holds up half of my first floor, but there are other places to put the thing. The instructions say where.