They received VC funding of $1mm. So that will buy those 3+ [1] developers some time.

According to an Oct 2010 article by TechCrunch [2] "Orbitz pays Hipmunk the standard rate of $3 per flight sold". Hopefully they did some renegotiations recently or have some other contract in place that generates Hipmunk more income.

[1] http://replicatorinc.com/blog/2010/11/alexis-ohanian-hipmunk...

[2] http://techcrunch.com/2010/10/06/how-hipmunk-almost-became-b...