In response to a booking inquiry specified by dates and number of people, an offer is sent by e-mail along with the rental terms.
The reservation is considered binding upon payment of 50% non-refundable deposit of the full amount of the reservation to the bank account:

SANTANDER Bank Polska S.A..
69 1090 2138 0000 0001 5656 5185

Payment title: Spirit Holidays rental from: ... .
The reservation is confirmed by e-mail after receiving the payment to the bank account. Payment of the remaining amount is made no later than 10 days before arrival. In case of available dates, it is possible to book overnight after paying 100% of the total booking amount. By making a reservation, you accept the Rental Terms.

Rental terms: rental_terms.pdf