just a few local 10Ks I have come across that may be of interest and that have relatively cheap entry fees
Antrobus Cabbage Canter - 10th October, Northwich. £12 entry. There is also a 5k and 3k (min age 9 - just noticed the discussion about the younger runners)
there are others but they are a bit further afield such as this one in mid-wales on 20th Nov
http://www.rhayaderac.org.uk/10mile.htm
I'm quite fancying the Southport one too as I think it is nice and flat - although the idea of winning a cabbage as a prize at the Antrobus one is quite amusing