As with everything the price of any service is what the market has to offer...the more the service can offer, like professional tax advice then the higher the fee.
Seems the older I get the more people want something for nothing...Not suggesting that this OP is stating that.
I think it is where anyone who thinks something is easy then why pay someone!! That seems to be getting more previlant these days!!
@BetterTax - What if there is no rebate? No charge? I know a few million self employed who would be up for that