Bookolo system, as its integration into your system is free for you. You only pay based on the selected business model of your choosing.
Commission model, you pay only when the customer books your accommodation through Bookolo. Commissions are around 4%. However, the minimum payment is 39EUR if the booking fee does not reach this minimum amount.
Monthly fee model, you pay a monthly amount based on the number of rooms and you will not be charged any other commissions for the booked stay.