Best way to Saga City from Tokyo

I'm planning to go to Japan in April but due to the cost to fly all the way from Jamaica I would like to know the best way(s) to get to Fukuoka City or Saga City from Tokyo. I'll also like to know the avarage cost and travel time for which ever way is recommended. I read about the bullet trains and the red-eye bus. Are any of these suitable for a first timer? Any help or recommendations will be greatly appreciated.

If you are going to do a round trip within 7 days, consider a 7 day JR Rail Pass. You will need to by a voucher for this before entering Japan. Not sure why you would want to go to Saga, it is a small town with very little happening. A day trip from Fukuoka might be a better option.

well my friend is currently living there so i'll be staying there. this JR pass can't be bought when i reach to Japan?

this JR pass can't be bought when i reach to Japan?

No, it can't.

http://www.japan-guide.com/e/e2361.html

I'm planning to go to Japan in April but due to the cost to fly all the way from Jamaica I would like to know the best way(s) to get to Fukuoka City or Saga City from Tokyo. I'll also like to know the avarage cost and travel time for which ever way is recommended.

I might suggest you to fly to Fukuoka or Saga from Tokyo Haneda. There are Narita--Fukuoka flights as well. Google ANA and JAL sites to search schedules.
As a foreign tourist, you're entitled to buy one of the Japan airpasses.
http://www.lonelyplanet.com/thorntree/thread.jspa?threadID=1...

Traveling to Fukuoka by Shinkansen Hikari on a railpass takes 6 hours with one transfer each way and another one hour to Saga. It's too long a trip after a long haul trans-Pacific flight.

Unless you're into a train travel, I'd recommend you to fly to save time and avoid possible exhaution.