Zoe Ellis, 28, received the money for walking around London with the advert for MicroBabies painted on her stomach.
Toy manufacturer Tomy rented her bump for the day to promote their latest product.
Zoe, who is eight months pregnant, said she was proud to host the advert.
"I think this is a really fun idea, and I'm happy to show off my new figure."
Tomy is now looking to recruit 100 expectant London mums to follow in Zoe's footsteps before expanding the idea nationwide if the campaign is successful.