To get this, you need the following:

ATLEAST 1 Basket.
The (Fully Grown) Horse.
Some money to begin with.

If you don't have them, do this:

Basket: It's at the Supermarket.

Horse: Barley will offer you to take care of the horse. Do it and when he returns you will be able to keep it. Brushhim and feed him honer/carrots, and talk to him. When you get the horse, it's best to make sure he has full hearts.

Money: Earn it somehow, I suggest getting a chicken, then place it's egg into the incubator until you have the most you can have. After this, get a cow. Also look for things in the wild.

Now here's how to get the money:

In Spring/Fall there will be a horse race. Enter your horse and bet all your money on it. Win the race. Then with the tickets, buy the necklaces, put them in the basket, rinse and repeat until either your basket(S) are/is full, or your out of tickets. Then empty your basket in the shipment box. The next day you should see that you have LOTS and LOTS and LOTS of money.

Thanks for reading and I hope you get loads of cash like I do! This is how I got the 100,000,000 house.