Range from the cheapest window sill replacement £360 (Styleline Interiors based in SP10) to the dearest window sill replacement £600 (K E Sainsbury Builders based in Sp3).
Comparing carpenter & joiners estimates for replacing a window sill gives you an idea of who will be better value but the best way to compare costs is to get actual quotes.
What to do - Get rates and quotes to replace a window sill in SP4 by posting a job with HaMuch and we will send it to carpenter & joiners in SP4.