Not sure about your area so can't offer any ideas on price. On the puppies I sold, they went to people I knew and I'm so incredibly grateful that they found good homes and not only that - I get to see them at least monthly!
I can understand how you feel - it's easy to get attached to them, isn't it? I agree that I wouldn't let them go before 12 weeks and just screen the people as best as you can. You could go to some yorkie breeder sites and get a feel for the questions they ask and then modify it to fit your needs. Good luck!