In the SW where i have just arrived, we call the same thing "Coyote Camping"- free remote camping on federal lands or wherever we end the day. Walmart camping fits in a different category for me -traveling to get somewhere and only need a spot to sleep. Boondocking or Coyote camping suggests a remote site with no services but interesting surroundings.
Our recent trip had one night of Walmart (couldn't find the FS road in deluge), one boondock, out of 20 nights, three nights with friends in their house, three in state parks ($24-Texa$ but had showers) and the rest in NFS or National Parks (Big Bend) all @ $7 per night (senior pass) and all but Big Ben with showers! Much more "camping" than usual for us.