Range from the cheapest cat flap installation £64 (OCC Construction based in NE10) to the dearest cat flap installation £152 (Martin Ballantine Joinery based in TS20).
Comparing carpenter & joiners estimates for installing a cat flap 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 fit a cat flap in DH5 by posting a job with HaMuch and we will send it to carpenter & joiners in DH5.