Rogerson Kratos are not the only ones charging like a bull for avionics.. for example last year I had to deal with Honeywell with the avionic repairs for our companies Citation X jet. Multi Function Display USD $15000, Inertial Reference Unit USD $22000, Radar (noisy in operation) quoted USD $40000). If you want the item repaired be prepared for a wait as it is their best interest to do exchange because (depending on the item) some of the exchange prices are close to outright purchase.
Not forgetting Cessna, for them to change the DVD player as the Citation X comes with two standard Zone 1 (USA) DVD's to change it to a multizone DVD it costs USD $25000.
You won't get a sympathetic hearing from them either as the customers on parts plans, airlines and the mega rich are more than happy to pay the asking prices.