dalej123,
Your point being different routes have different prices?
You need to look at the directly competing routes to get an idea of price. Last time I checked Norwich isn't anywhere near Plymouth so you'd expect the cost to be different.
What are Exeter to Guernsey flight costs with flybe? (slightly more relevant)
First thing tomorrow morning £61.39, seems like flybe are cheaper on that single sample. Not bad for a last minute flight