Hosts may ask for extra monetary contributions for cleaning, electricity, heating, etc. However, this information must be written in "additional information" on their profiles.
Additionally, some countries/regions may ask for tourist/city tax that you need to pay. We strongly suggest to check with your exchange partner and/or local authorities.
In the event that there are no pre-established rules, both parties must reach an agreement on these details during their conversations.
You are free to organize and arrange everything with your guest or host.
We strongly advise you to discuss these details BEFORE finalizing the exchange to avoid bad surprises later.