Service areas :
The service areas are traditionally intended for motorhomes, but can of course accommodate vans. This can be an interesting option in touristy and busy areas, where it is difficult to find an authorized spot for the night.
They also allow to have access to electricity, to fill the tank with clean water and to empty the grey water.
Budget: free to a few dozen euros depending on the area.
In France, municipal or private service areas are very numerous, more than 4000, and many applications allow to locate them.