As smooth vizslas are becoming more popular some 'breeders' seem to charge as much as they like rather than sticking to what most people are charging. Six years ago( seven in September) we paid around £400 for our fist vizsla then 2 nearly 3 years ago around(not going to put exact figures here!) £500 for our second and this figure seems to have risen again, looking about at what different breeders are charging.
Of course price is not the only deciding factor, you can pay over the odds for a badly bred, not well cared for pup and you cna also get a well bred and cared for pup for less than what alot charge, its upto the breeder, and the potentail buyers-supply and demand has been talked about alot on here.
So I'd say anyhting from £500 to £800, but beware, I know someone who bought a smooth vizsla from a 'friend' for £400(reduced by £100) and he turned out not to have been KC reg'd, typical story that the breeder said the papers would follow, not nice as the dog ended up in rescue :( but now has a new home :)
Vizslas are a great breed, feel free to join and ask more questions, they are a few of us on here mad enough to own 'the ginger ones' :D
Emily
Ps Have a look at these sites http://hungarianvizslaclub.org.uk/hvc/default.htm and http://www.btinternet.com/~hvs.vizsla/hvsintro.htm (copy and paste:)) for a bit more info, if you haven;t already that is :D