another solution for 6 by turn 4 would be this
Turn 1: Buy Chancellor
Turn 2: Buy Talisman
Turn 3: Play Chancellor, discard deck. Play talisman, buy WV, gain another.
Turn 4: Play two WV and chancellor. Play talisman and 3 coppers. 6$, 3 buys, 3 actions played and talisman=6 peddlers.
EDIT: oops, should have enclosed it in spoiler tag, I guess, although it's not a solution.