I want to purchase a pair of glasses with clip on for my daughter. As the new semester is coming, she needs a new pair of prescription glasses. Her prescription is just about -3.50. and her face is round not big. She also wants the lens with tinted. And the frames are made of titanium. How much does it cost online optical store? Is it cheaper than local store? I just bought one pair last year for $90 in local store. I think it is a little expensive. So I decide get one online now. which store is best? Who can give me some advice? Thank you !