With those prices, you'll have to be preying on the uneducated people who can't look for another service. Another service on the forum charged 0.0076BTC for a prefix with difficulty 888,446,610,538. That is over 6 times more, for the same difficulty. Consider lowering your rates, or else you won't be getting m(any) customers. Won't link it here, but if you want to know the service, send me a PM. (they also do > 6 character addresses for free)