According to Plaffo the new Nokia 800 will set you back 499 Euro’s or about 687USD. This from the chart you see above and a what seems to be a guess. The above chart seems to be in order of most expensive phone to cheapest. The phone above the Nokia 800 cost 499 and the one below it costs 429 so 499EU seems to be the upper limit that the Nokia 800 would cost. (435EU or 599USD would make more sense to me.)
But I would need to see the official specs of the 800 before I can give you a real opinion on the price however…I will put the full chart below so you can see where it lands price wise with all the other phones.