We've just played with Tax event.
I used the opportunity to add two debts to several piles, early in the game.
I am right in thinking that the next buyer of a card from the appropriate kingdom card pile gets all the debt on that pile and not just one of the tokens.
That's how we played it.
That's how I interpreted the rules, but the question was asked by my youngest (31years old).
All of the Debt tokens. The symbol for the Debt tokens you take is just a copper hex. If it were only 1 Debt, it would've had a white '1' inside to denote that.