Most CHAdeMOs are payable, main operators are Vattenfall and Fortum, and they charge 3 SEK/min (~0.30 EUR/min), and require RFID or SMS payment (which would require a Swedish SIM). Those that are free would be at car dealers, like Mobility Motors Bromma. Vattenfall say they will launch the app "Ladda elbilen" soon which can be used for payment.
AC chargers found in parking garages or shopping centres are typically free (but in public parking garages you'd have to pay for the parking itself), and are normaly 1 phase 10A-16A.