Anyone actually say during an interview that the reason they want the job was because they need money?

You will almost always be asked why you want the job, and money is implicitly understood for everyone that applies to the position. Don't bother mentioning it, it will only hurt your chances. IMO the way to answer that question is to link the job to your ambitions i.e. as a stepping stone, or your past experiences as a logical continuation and your capacity to be an asset, and finally any other motivations you can think of.