Money is an important symbol in the play, not least because its relation to each character tells us quite a lot about them. Eben buys out his half brothers, so he can have a better claim on his late mother's land. With Eben, pride is all-important. He believes himself entitled to the land, because his mother died working so hard on it. For him, money is a means to an end, a way of getting what he wants in life.
We see this later on in the play when Eben vows to follow his half brothers to California, makes his fortune in the Gold Rush, and then returns to buy the farm, taking revenge on his hated stepmother. His stepmother, the voluptuous young Abby, is initially presented as something of a gold digger. Later on, it is her unhinged passion for Eben that takes over and leads to her murdering their baby. But Eben is convinced that Abby has been using him all along to get her grasping hands on his mother's farm.
To some extent, money corrupts the soul of virtually every character in the play. It separates them from the land, from their true selves, and from what they really are. Land is not seen by the characters as a home or a place of settlement; it comes to be looked upon as nothing more than an economic commodity to be bought and sold for profit. Money corrupts the innate natural beauty of the land as well as the relationship of the various characters to it.