Before watching the movie:
Among “contrived reasons for two people who wouldn’t normally interact to be stuck together”, “I will pay you a thousand dollars to be my girlfriend” is a pretty contrived one. It looks like he’s not even lonely, he’s just trying to increase his social standing.
It looks like there’s a little inverse-Pygmalion happening, where he brings her into his life and she helps him fit in? That is probably not what happens, but if it is, that could be a pretty forward-thinking concept for late 80s Hollywood.