You can with the following loop:
Pick Favor
Purchase Ring of Greed
Purchase cheap item (-500*.65 == -325 g)
Drop cheap item
Teammate picks up and sells cheap item (+500*.8 == +400 g)
Of course, this lasts only as long as the 'feeder' has gold reserves. You could then alternate by after the first player exhausing their gold, the second player picks up their favor item (Magic Coin Pouch) and then buys items for BOTH players, which he would be able to do since he would have a huge gold reserve (larger than the combined total of both players at the start).
For efficiency, you wouldn't want to do this at the start, but rather in the mid-game or so. Say, second shop. If you didn't buy anything first shop, you would easily have 3k and you could then buy roughly 6k worth of items. Each.
But yeah....