if the prices are reduced subsequent to possible relegation, it won't be by anything like you're suggesting fatbury. i imagine it'll be £19-£20 for arkells/nationwide and £12/£13 for town end.
i think supermarine charge less than a fiver as well.
And just to back that up, I went to Canvey Island last season and even then they were charging £11.00. Braintree Town are charging £8.00 in the Rymans Premier and I even payed £6.50 for an FA Vase game at Sudbury last weekend and they are Didcot's level.