Try the Cambridge Aero Club. Last time I was there a DHC1 Chippie was £4/10/0 per hour dual, although that was a few years ago and the price may have increased slightly since then.
Use "Search" on this Forum but I seem to recall seeing $225 - $250 per hour is about average for a C172. Keep in mind the cheapest is inevitably far from the best and you may not be very happy.......