My littlest Campbell is awesome at using the potty. She has a Dora potty seat for inside the house & a Pooh Bear potty for in the car.
When we're out, I just open up the barn doors & she goes right there in the back of the Excursion. Like so:
he refuses to use "toilet papers" when we're out. Yuck.
If she doesn't go, she saves the "toilet papers" for later by tucking into her potty handle. I would say she's frugal because of that, but she just wasted 9 perfectly useful pieces of toilet paper...she BETTER save that usable one.