So Ferry can do some things that have never before been possible. A couple off the top of my head:
-Buy a Border Village, gaining a Grand Market (or other $6 or $7 card, but this gets around the Copper restriction).
-Use Band of Misfits as a $5 or $6 card.
-With Haggler in play, buy a card, gain another copy of that card, or one that costs $1 more than the bought card.
-Trash Catacombs, gain a $5 or $6.
Others?