I have traded a Beretta 9000S in to a LGS to get a TCP. Dumb trade on it's face, -Beretta +Taurus. But, I hated that gun, I've said it over and over here... Probably some guys sick of hearing me say it.
Suffice it to say, I've only broken his rule once...
I spend too dang long deciding what to get and saving up the money for it to not be exactly what I wanted. I'm NOT a spur of the moment gun buyer.