Welcome to the forum. 350Z prices are all over the place these days but you could get a facelift 06 model on that budget. Alternatively, you could pick up an 05/55 model for a little less, Don't take too much time looking for one with a Nissan SatNav, aftermarket ones are much better and as rtbuiscuit says, it runs around 28 mph per 1,000 revs and is surprisingly economical on Motorways. It's very important that you inspect the service record as well. If you see one you fancy then ask someone from here to look at it for you, most will be glad to check it out for you.
Good luck!
Pete