I was surprised when in the queue at Taly for round one when I heard people being charged £10 to enter and then shocked when the guy infront of me was charged £20 to do two classes!!
I was going to enter two, but that changed my mind along with the warning that if you did two classes you'd get penalised if you were racing in your 2nd class when you should be marshaling for your 1st!
The Mid West regionals that I've done have charged £5 and £6 depending on the club which is a bargain! £10's too much in my opinion anywhere inbetween would be ok.