The balance on arrival is the part of the fee settled in the room once she is there, in cash of any major currency, by card or in crypto.
Balance is the word for whatever is still owed when she reaches the door. On most bookings that is the second half of the fee, the first half having gone ahead as a deposit. On one kind of booking, a same-day session of one or two hours for a client the house has looked after before, the balance is the entire fee, because that is the only booking paid wholly on arrival. It is the exception, and a narrow one.
Cash in any major currency. A traveller who landed with pounds, dollars or francs and found every exchange counter shuttered need not go hunting for a machine at two in the morning; the sum is worked out at that day's rate. Card, for anyone who would rather keep banknotes out of the evening. Crypto, for those who prefer it.
At the beginning rather than the end. Settling first means the rest of the night carries no arithmetic, no counting on the nightstand and no awkward pause when she is leaving. Have it ready before she knocks: notes counted into an envelope, a card within reach, a wallet already open on the phone.
A first booking of one hour is EUR 180: EUR 90 goes ahead as a deposit and EUR 90 is the balance. An overnight is EUR 1,250: EUR 625 ahead, EUR 625 at the door. A returning client asking for two hours tonight pays the full EUR 360 as the balance, since that particular booking carries no deposit.
The balance is always a ladder figure less whatever was paid beforehand. The office writes both numbers into the thread at confirmation, so the amount at the door never comes as a surprise. The rates themselves are on the prices page.