my missus runs in Mizono Wave Harrier 2's. She's been through umpteen pairs in the last xx years and they have done her proud. I'm sure (if you shop around on the interweb) you can find them for about £40ish...
edit to add...
I should have added that she ONLY runs off road... and has gone through the mara distance about 35 times in races in the above shoes.... no blisters, little slippage in the mud, good grip on the hard stuff too. (they do pong though)!! 
Edited: 06/12/2011 at 18:52