I have noticed in my calendar if you book ahead you can pay half now, the rest later. This is absolutely now and only in some months ( from October on in my case). This is copy of the info I got when I tried to look in my calendar yesterday
"When booking you pay for authorized credit card or PayPal, you will be able to pay a portion of the total amount now and the remaining amount of the impending arrival.
Under this option you will not be charged any additional fees.
What happens on the day of my second payment?
From your side anything. The second payment will charge the due date, and payment method used to make the booking.
If there are any problems with this payment, we will send you updates by e-mail. If we are unable to settle the remaining payment, cancel your reservation on your behalf and the money will be refunded according to the cancellation policy the host."