No people she's not singing about being a prostitute. She's talking about being in a relationship. She's letting him know that even if it's a temporary thing, she wants him to put forth the effort. Every relation has it's cost. Like a plant it won't grow if you don't take care of it. Actually take the time to take care. It's not easy. The guy might be looking for a one night stand, she lets him know what she wants. She doesn't want some disgusting pig, so even if she agrees to this one night stand, she wants him to make it worth her while.
Maybe that's it. But I will definitely turn pink if she is indeed talking about prostitution.