The best net price seems to be when new machines are introduced to the market.I did what luana did, trading my 7700 up for the 8900, he gave me 2K trade in value. It was worth the difference to me because my original and replacement 7700's were both lemons.
Incidently, the 8900 is the perfect machine the 7700's should have been...
If you do pretty much nothing but patchwork you only need a straight stitch machine, rather than one with all the bells and whistles. have you used all the bells and whistles on your 6600?
all you can do is ask, our opinions are pretty much worthless
I keep my 6600 in our 5th wheel.