I want a house in the magic quarters. What's the easiest way of getting Magic Coins, including cheat codes?
Also according to IGN, you can evict a family from their home and move them back in. When you do so, the Mystery Man will come to your house and drop a Magico starter kit which contains 35 Magicoins. You can save the coins and do this as often as you like.
You can also go to Magic Town with a Sim with maximum logic and perform on stage all day long. The maximum output from this method for a day appears to be 675 Magicoins.
As a side note, a Sim can only carry 32,767 Magicoins at once, and MagiCo's Bookshelf of Dimensional Storage will only hold 30,000. (Source)