Robert Walton has embarked upon a perilous journey to the icy wastes of the frozen North. This is no mean undertaking and would've cost a considerable amount of money. In addition to the costs involved in hiring the ship—not to mention marine insurance—Robert and the other crew members need to be fed and watered throughout their journey. All in all, it's a pretty expensive business, which raises the question: Where did Robert get the money from to pay for the expedition?
The answer is that Robert is independently wealthy. We gather through snatches of his letters home that he inherited a large sum of money. This gave him the financial freedom to leave his native England behind and explore the wider world. Yet it's notable that Robert's wealth doesn't seem to bring him much happiness. There's an empty void in his life which he constantly feels the need to fill through hard exertions of one kind or another, such as physical labor and going on dangerous whaling expeditions.