I can see that, though the wording doesn't quite work out that way. The wording is set up more as a general rule, and not as an effect of the event.
That's because the Event (or in general any 0$, +1 Buy, no "once per turn" restriction Event) emulates a rule change. Gee, that's what this is all about, a stab, probably not a very good one, at the upcoming "gain now, pay later" mechanism.
But I don't want this rule to exist in every game, so it should be conditional upon the Event being there, and for practical reasons I obviously want the rule text on a card.
Just read in this thread about Ankenaut's
Mortgage. According to Ankenaut it is totally game-changing and feels like a variant. I wanted something less radical though, hence the steeper costs via interest (Mortgage can be "payed back" at any time) and the restriction to only two cards.
There's no reason to ever buy that event that I can see.
Buying the Event costs nothing so it is moot to discuss whether you do or do not buy it. All the Event does is specify WHEN, namely during the Buy phase.
All this confusion on your part is obviously due to the fact that you do not seem to grasp the mechanical equivalence of a rule amendment and an zero cost Event.
Boils down to the usual error of rule lawyering before getting the mechanics. First you gotta consider how something works and whether it works fine before you express and formalize it perfectly. I'd rather discuss something actually relevant e.g. whether the implicit interest rate should be 1/2 and 1/3 and whether -3VP sounds like a decent penalty for default on a Loan.
"Take up to 2 loan tokens. You may purchase a card from a pile with a credit token on it for $2 less per loan token taken this way."
This wording does not work at all. You should be able to take as many Loan tokens as you want and the virtual coins you get via Loan tokens should be splitable among buys (I already explained why pooling the Loans and the total cost of all eligible buys is quintessential). Hence my awkward "reduce the total cost of buys of cards with a Credit token on them by 2" wording.
Here is the new version, a mixture between Gubump's (thanks man) and my first wording:
CreditCost: $0
Type: Event
+1 Buy
Take any number of Loan tokens and reduce the total cost of buys of cards with a Credit token on them by 2.
After playing your Treasures but before buying cards, you can pay back any amount of Loans via spending 2$ per Loan. If you don't, -$1 per Loan . If you already had $0, take your -$1 token. At the end of the game you get -3VP per Loan token which you did not pay back.
Setup: Put a Credit token on two Kingdom Supply piles.