I do contract work for a company in the travel industry and the founder of that company told me that they did basically the same thing when they started. He set up a website with hotels, etc. When customers called in, he would make the sale and afterwards call up the hotels and try to book rooms etc. If needed, he would call back the customer and change the booking. Basically optimistic strategy with rollback :-). Interestingly, he told me that at first he had no agreements with the hotels and had only a vague idea of rates, etc. He would just make it up as he went along, meaning that sometimes they would get a huge margin and sometimes he would take a loss. After he booked several rooms with a hotel he would then call them up to set up a contract. He apparently also started up the whole thing carrying just enough debt to cover the billing gap. Took no outside investment. Totally ballsy way to start up a travel company, but it worked pretty well (Doing hundreds of millions in sales per year these days).