Take anything in the super market, for example, eggs. A huge number of people buy eggs. A relatively small percent buy with food stamps those same eggs.
Where else can you get a dozen of anything, cleaned, packaged, shipped, shelved, priced, registered, and bagged for little more than a dollar?
No frills clinics are the wave of the future. My doc prefers a clean transaction between himself and patient. Much easier for him than the enormously expensive paperwork route of insurance companies and/or government.