We often remember The Invisible Man as the story of an isolated mad scientist fighting against the larger community. But there's a whole other issue that often gets forgotten: money. The Invisible Man may be motivated by his interest in science (or power), but one of his first and main problems is that he's just plain poor. If he only had money, imagine how different this story would have been: he wouldn't need to steal, he wouldn't get into fights with his landlords, and he wouldn't need to work a job he doesn't like. In some ways, money is the driving force behind all of his explosive actions. Isn't it always?
The Invisible Man is really about capitalism and its mysteriousness. The Invisible Man himself is a literal version of Adam Smith's "invisible hand of the market."
The several scenes of theft in the book show us that wealth doesn't last.