Thanks for explaining your different definiton. One more question - in this case how is Miss Taylor being traded as if she did not have intrinsic value? My reading of Miss Taylor is that intrinsic value was the only thing she did have.

I'm rather doubting that JA intended to make any point about Miss Taylor being traded like goods. As far as I can tell, Mr Weston wanted Miss Taylor because he was in love with her, like any of JA's heroes, and Emma and Mr Woodhouse, so far from trading her away, were sad to give up their friend.