On a recent trip I stayed at some WM's on the way there, (1100 mile trip,) and the way back. I spent at least $100 at each stay, be it gas, supplies, or both. My maximum stay was for about 14 hours, I stopped there due to a blinding rain storm during rush hour in Knoxville, TN. After the rain let up, I did my shopping, and discovered their gas was only $2.98 so I filled up both the MH & the toad, then left after the morning rush hour.
I don't put out my slide, or jacks, just shop, eat, sleep, and go. The reason I usually stop at places like that is for a short break to make me a safer driver, not camping. In my younger days, I'd driver straight through, it would usually take me about 17 hours to run an 1100 mile trip. In the MH it takes me about 3 days.