(source: Iceberg Slim: Pimp, The story of my life)

Please help me to understand what does a bundle in the damer exactly mean here:

The section that contains the expression:
I thought: This beautiful white bitch has class. She sounds like an egghead. With wheels like that she's probably got a bundle in the darner! Maybe she's got some rich sucker in her web.

Background:
Slim accidentally meets a beautiful girl and starts considering to get to know her and even making her his wh*re because the nice car and the attractive appearence of the girl draw his attention.