What the tolls actually cost you
ETC needs two things: the transponder built into the car, and a separate ETC payment card. Rental vehicles almost always have the transponder; you rent the card alongside it for a few hundred yen. Nobody rents the card on its own, so sort it out when you book the van. Enter ETC lanes at 20 km/h or slower.
A campervan registered as a camping car pays the ordinary-car rate however large it looks — the classification follows the registration, not the size. Keep the vehicle inspection certificate handy; toll staff sometimes ask to see it. A kei-based camper stays in the kei bracket, but one widened onto white plates moves up to ordinary.
The nationwide Japan Expressway Pass ended in 2023. What remains are four regional passes — Hokkaido, Tohoku, Kyushu, and San'in–Setouchi–Shikoku — available on a foreign passport plus a licence valid here, and only through the designated rental companies. Worth knowing separately: at 29 michi-no-eki you can leave the expressway, stop, and re-enter the same interchange within two hours without paying as though you had exited. It needs ETC 2.0, and it exists because some stretches run 25 km with nowhere to rest.