hi. first of all i advice you to make a search for related threads, in this section we have threads about N9's broken touch screen.

about replacement and price - i had three N9s broken (in other times) and every time i bought the display from ebay finding cheapest, and the cheapest is about 60$. no problems.

PS: if problem, as we know in ebay with paypal you can retunr it and get your money (ofcourse some costs to shipping back). but i never had a problems with it.