Last year, I bought an open box M4A89GTD PRO/USB3... its not the 890FX; but its the 890GX...
Aside from not getting any of the drivers with it; I got lucky and it came with all the other accessories.
I got lucky and got a great deal on it, and its proved to be a rock solid board. So if the 890FX version is available (M4A89TD- PRO/USB3) then go for it, as it would be perfect for your price range.
Otherwise, hold out a little longer for the 990GX/FX to come out, should be within the next couple months and when it does, it will push the price of the 890's down a little more. Honestly, I jumped the gun on my 890GX when I bought it, when I really wanted the 890FX but got impatient waiting and working on a budget, I jumped the gun and ordered the open box 890GX. Glad I got lucky with it though!