In Sweden there are two different kinds of road toll schemes, Infrastructure charge and Congestions tax.
Both schemes uses fixed gentries and the vehicles passing is identified through Automatic Number Plate Recognition (ANPR). This means that you don't need any kind of on board unit or sticker do drive in Sweden.
Vehicles registered in Sweden and vehicles registered abroad must pay the bridge tolls in Motala and Sundsvall.
In Stockholm and Gothenburg there is a system of congestion taxes. The tax applies to vehicles registered in and outside of Sweden.