Or, you can play Monopoly and ask yourself - where did the money come from? And what is this Property? You might incorporate ideas such, as lease with option to buy, or just options, or seller financing to buy, or buy for cash directly from Owner, or a number of other ways to buy - but do keep good records.
At the end of the game - the property goes back to the banker - an anonymous figure.
Example what if you own Park Place and another owns Boardwalk - Perhaps you enter into a deal with the Owner of Boardwalk to lease Park Place to him for $300 each time around the board. While he can now improve the property due to his interest in it, he may have a term limit on the lease [20x around the board] and if he does not execute the option to buy, the improvements revert back to the remainderman - you. Makes the game a bit more interesting and a lot more real.