What is the cheapest Nikon brand External Flash for a Nikon D70 Camera?

I need a flash, i'm a novice photographer, just for hobby so I don't want to spend tons of money. Any info on a good and cheap Nikon flash for a D70 would be Really appreciated!

Cheap: Sb-400
Good: Sb-600 or 700

First, don't go for the cheapest which is the Nikon SB-400.It is limited to using bounce flash in landscape (horizontal) orientation plus it lacks the manual control often desirable in some situations.

A better choice, in my opinion, would be the Nikon SB-700 which allows use of bounce flash in portrait (vertical) orientation as well as in landscape orientation. The SB-700 also gives you the option of using manual control when needed.

Here is information on using bounce flash:

http://www.wikihow.com/Use-Bounce-Flash-to-Improve-Your-Photography

http://vividlight.com/articles/3311.htm

I have always found it better to have a feature and not need it than it is to need a feature and not have it.

First choose a flash where you have power control output. (not sb400).
next flash are rated by guide numbers. Which tell you how much light you need. How far will you stand? How much power do you need?

personally, the situtation changes when i need flash. So i need high power than i can power down and adjust. For that reason i would choose the sb700 or 800. There have been many instances where i needed full power. I would not have been able to get the shot without the high output of te more expensive flash.