Geez louise people it's not that difficuy to grasp!!
The money was representative of her nasty past, of her time spent selling her body for money, a time which she is ashamed of and doesn't want to be reminded of anymore. So to cleanse herself of her guilt of it, she throws all her dirty money away, allowing her to start a fresh life with her new love and move on from it. If she relied on that money anymore, whether for food or for gifts or for dates or ANYTHING, then she would still feel the guilt.
And if anyone replies to this going UM WHY WOULD SHE THROW MONEY AWAY???!! SHE COULD SPEND IT ON THINGS LIKE SHOES AND STUFF AND GIFTS then i will ram my fist up your butthole for missing the point of the story completely.