It is completely free of charge to sublet a home with

Renthia simply adds a 10% service fee on rent you decide.

E.g. You want to rent out your home for 10,000SEK/month, Renthia adds 10% and advertises your home for 11,000SEK/month. You get 10,000SEK, Renthia keeps 1,000SEK as service fee.