Range from the cheapest window sill replacement £300 (PHM based in SS14) to the dearest window sill replacement £520 (Top Marks based in SS7).
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 SS17 by posting a job with HaMuch and we will send it to carpenter & joiners in SS17.