Last night, in Wyoming, I stayed in the lap of luxury: Motel 6, Laramie. It was cold (40s) and very windy (sub-freezing chill factor), so it seemed worth the 40 bucks. In Kansas, though, the weather is a lot more mild, and every night I can spend outdoors is money saved (and more time I can spend in Europe, where hostels about $20/night). The car I am in is packed with luggage, so there is no space to achieve the critical element: bringing my legs to the same level as my head. (I can sleep sitting up, but it isn't comfortable.)
Tonight, I didn't have to look very far. Kansas has big, spacious rest areas where you can usually get away with camping under cover of night. (Camping on the ground wouldn't work at most rest areas in other states, where space is at a premium.) This rest area near Russell has a vast area of mowed grass behind the restrooms, big as a football field. There are about six 18-wheelers parked at this rest area for the night, but I'm the only car, so I've made myself at home. I have set up camp behind a big bush in the middle of the field, so it's impossible for anyone to detect me. (The car is obvious, but it's normal for it to be parked here.)
My "camp" consists of a sleeping bag, a camping mattress and a 6x8 tarp for a ground cover. The low temp tonight is expected to be in the 50s. Very little wind and a clear sky full of stars. Since it is only 9pm, I'll easily wake and break camp before down.
Here's my exact location if you care to join me.