There's a dye trader in every major city that does exactly what you are asking.
If you are selling to other players take the median between what the trader is buying for and what the trader is selling for.
Best of luck.
Price Check on Dyes!
Levi Garett
Levi Garett
I think that's a pretty good deal for both you and they buyer. Check the dye trader I can't get online right now...