I think an Ambanja x Ambanja pairing will sell for more. I don't think that adding Faly will make the price higher than it would be for a pure Ambanja. Unless you're a big breeder with an impeccable reputation, it seems that no one can get away with selling crosses for anything but under what pures cost. I got mine for under $200.
Here's my Faly-banja male, coming up on two years old. I think he's beautiful but many may not agree with me. I chose to breed him to another cross for the sake of curiosity, and have been able to get people on a waiting list for nearly all the eggs. So breeding that cross is up to you.