how much would you think a 2 letter .org domain would cost


like for example:
9e.org
9g.org

like that style

If it was 2 "letter", quite a bit. Any large company might want their "Monogram" as a URL...if for no other reason than corporate vanity. But, a letter and number...not so much...

so would like $600 be good?

If I was offered in the neighborhood of $600 for a letter/number domain I would seriously consider taking the money (especially if its not a .com) Unless the domain was as meaningful as something like A1.org T3.org or V8.org...well you get the picture...then I would hold out for at least 4 figures.