I am developing a niche travel directory site. When the user does a geographic and other criteria search, they will arrive at a dynamic search results page with a list of travel options provided by various vendors. When they click on one of the results, they will arrive at another dynamic page that provides some detailed info about that travel option, with a link to its webpage/site. The model I'm looking at is to charge the vendor a flat rate for each click-through from that link to their site.
This is different than putting up banner ads and Adsense, and most of the vendors I have in my database are not in any affiliate programs, and many aren't on any competitor directory sites. Because my site will be so specific to what the vendors are offering, its traffic will be very high quality for the vendors.
What I'm trying to learn is what a good, competitive click-through rate would be for this. I'm open to starting low and moving up and even offering, to start, a ceiling per year of how much I would charge the vendor.
I can't seem to find any suggestions through travel industry forums - it appears that this is something other travel site operators are keeping close to their chests. Also, doing google searches of "flat ppc price" or "flat cpc price" isn't yielding any relevant results. Instead I find only info about auction-based click-throughs and Adsense.