The card I usually see with this name has something to do with putting coin tokens on supply piles. Cards in those piles cost $1 more per token on top. There are plenty of variations within that theme, such as whether there can be multiple tax tokens or just one that's moved from pile to pile.
Deceptively, it's more damaging than Embargo, because with Embargo the Curses can run out, or there can be a way to circumvent them (Watchtower, Trader), or you can have a junk-tolerant deck (heavy drawing, trashing, or trash-for-benefit). By increasing costs, you really can't get around the penalty. Even most gainers have cost-based restrictions.