Question: I read the instructions as stating that you can place an action and/ or a money and/ or a property. But others say you can do any combination of the three in any of the three piles.

Answer: 
The three cards can be any combination of properties, actions, and/or money. From the rules (abbreviated for clarity):

> 
> PLAY UP TO 3 CARDS from your hand, onto the table in front of you. You don't have to play any cards if you don't want to. Play your 3 cards in any combination of the following: A, B, and/or C.
> 
> 
> A: Put Money/Bank cards into your own Bank
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> B: Put down Properties into your own collection
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> 
> C: Play Action cards into the center
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> 
>
You can play any three cards from your hand during your turn. These three cards are not otherwise restricted in type; you can for example,

* Play three *Deal Breaker* cards and potentially win the game
* Play three *Pass Go* cards to draw a total of six new cards
* Lay down three properties to either form a set (and possibly win the game immediately) or to complete existing partial sets
* Play three *Rent* cards, either using different properties/sets or the same property/set as the base
* Lay down three *Money* cards in your bank

You can also choose to end your turn before playing any cards at all, let alone all three cards allowed.