One of the funniest domains I've read for appraisal. I'd say selling to the right person could easily pull mid-high $x,xxx. On the other hand, $1,000 might be a reasonable offer since (as proven by the previous poster) many purchasers might not get the fap reference.
Great name.
BTW, for anyone else who doesn't know. Check the UrbanDictionary.com definition:
The onomatopoeic representation of masturbation. Often used to suggest that something is attractive.
Did you see those Natalie Portman pics? *fap fap fap*