One of the most profitable ways to make money on the Internet is to earn money from tourists. And such a wonderful opportunity is provided to us by the service "Booking.com". The advantages: you do not need to deal with API and large payments. Booking pays its partners from 25 to 50 percent, which is higher than many of its counterparts. The only minus: payments are made only on PayPal and the minimum is 100 euros. Otherwise it is excellent.