About £1m and up for a decent example of a Spitfire, with very high running cost. There are very few ME 109s available. Quite a few Mustangs.
You can buy a new build FW 190, possibly the best of all the fighters, here:
http://www.flugwerk.de/
Note, they are not replicas, they are actually new build authentic aircraft which have been awarded continuation serial numbers.
Happy flying!
QDM