There are no upfront costs with AirBnB. It's free to list and then they charge hosts a 3% to 5% booking fee every time a booking is completed on their platform, depending on your cancellation policy. This fee covers the cost of processing guest payments and comes out of the host payout.
A 5% fee is charged to hosts that have Lodgable cancellation policies that most closely match AirBnB's strict and super strict cancellation policies.
A 3% fee is charged to hosts that have Lodgable cancellation policies that most closely match AirBnB's flexible and moderate cancellation policies.
You can learn more about AirBnB's cancellation policies by clicking here.