I'd say maybe high $xx to low $xxx Unless i'm dreaming it blonds is spelt blondes, but I can imagine that it could get in some type in traffic. Undeveloped though i'd say high $xx to low $xxx
Nerdy language moment : blond can also be spelt blonde - it's practically the only adjective in English that has feminine and masculine forms i.e. blond referring to men and blonde referring to women. However, many people no longer make the distinction and I doubt the person on the lookout for this site will care whether it's teenblondes or teenblonds!!
Great domain and perfectly applicable to the adult market. People after websites such as this would probably want to find TeenBlonds! I'd give it a mid $xxx. Try and sell it to an end user rather than a reseller to get the best money out of it.