Is there anything out there can be considered as THE best affiliate travel booking engine?--- the answer is clearly nada, zero, zilch! Why? For one thing, because people expect to get it for free, almost all affiliate engines that’s available out there are not flexible, from integration standpoint, look and feel customization, markup/markdown margin capabilities, content uniqueness for search engine marketing, limited to regional booking processing due to credit card fraud, etc. The list just goes on and on in terms of lacking of features and flexibility. And another why?, because the affiliate booking engine providers has spent millions upon millions of dollars building their booking infrastructure based on their business and revenue model, not solely towards affiliates. Now, you are asking, what’s my choice? Well, if you cannot afford to deploy a master-license based booking engine, then you’ll have to settle with free private label affiliate programs out there. But you'll still need to spend money to build a website to integrate the engine, therefore, it is not entirely free. Nothing is free in this world to build a successful business. With years of experience, I have seen very few online entrepreneurs has ever made it big powering their site/s with a free affiliate booking engine. Most online travel entrepreneurs doesn’t realized that operating a travel website or portal requires more than just a booking engine. Adequate funding to enhance, maintain, support and market the site requires varying degree of manpower and skills resources to be successful. I’ve encountered one-too-many travel website operators who complains that the booking engine doesn’t work and I’ve asked what online marketing strategy initiatives they currently have? And most typical answer I’ve got is, “What do you mean? We have a website with your engine in it and no one is visiting the site, therefore no one books it.”- an "if you build, they will come" syndrome, thinking that people will just find their website without promoting it properly. It may sound too simple-minded occurrence, but I shit you not, there are many of those wannabe online travel entrepreneurs out there who just love the whole idea having a travel website and has no idea what it takes to operate it. Then what’s your option? Allocate a budget and hire someone with experience to find you the “right” booking engine based on your planned business and revenue model. Don’t have a clear written plan?--- I suggest that you do not proceed with it until you have one. If you have a plan and budget, then why would you hire anyone to look for the right booking engine instead of doing it yourself on the net? Unless you have experience deploying numerous booking engines and years of experience evaluating differing booking engines out there, then you can spend months or even a year to do your own never-ending research, calling vendors and scheduling demos. That is of course if the vendors feels it’s worth their time talking to you and answering your questions in details, due to the fact that some wannabe online travel entrepreneurs think and treat these vendors as if they are a non-profit organization to expect that the vendor's products and services are being offered for free. There are at least nearly 100 variables that one should find out what a booking can do, features-wise - download a courtesy copy of our Travel Technology Matrix for Booking Engine & XML Connectivity Sourcing Services.