Yes, please read the info that Going Quackers said to. And, not to be critical, but shouldn't you have determined the cost of owning a duck before you got one? They are not expensive normally, but they need good food, treats, a safe environment which is predator proof, and if there is an issue, veterinary care. They are wonderful pets, but they need more than the basics to be happy and healthy. And, yes, ducks should not be alone IMO. They are flock animals and need at least one other companion, two is better. But you have to be careful, you don't want to end up with two boys and one girl. That is a whole other issue.
So, I suggest you start doing some reading right away so you can make sure Lucy is well taken care of. She is really adorable.