Flight to okinawa

can anyone help with a cost of flying from Fukuoka/Hakata to Nara/okinawa? Is it better to do this in advance or when i arrive at hakata?

can anyone help with a cost of flying from Fukuoka/Hakata to Nara/okinawa?

I assume you mean Naha.

JAL and ANA operate on this quite popular route. You should be able to make reservations through your local travel agent. Or use an air pass. More details on air passes here:
http://www.japan-guide.com/e/e2364.html

Is it better to do this in advance or when i arrive at hakata?

Depends on how early in advance you arrive in Hakata. I recommend to make reservations as early as possible, because the cost of the ticket is likely to increase the closer you get to departure date. You can make reservations starting two months before travel date. Possibly earlier if you book from overseas.

If you are coming to Japan from overseas and wish to use the Welcome to Japan fare from either ANA or JAL; you won't be able to book the flight until two months prior to your flight to Naha. You'll have to book the flight from overseas, also. You will need to send them copies of your tickets to Japan plus a few other items before they will issue the discounted fare. It's really pretty painless, though.

Thanks for your answers very much appreciated