Lets take this hour to be an average hour. Over 12 hours in a day that the mall is presumably open, that's 22*12 = 264 leads.
> the mall isn’t behind these giveaways; they merely rent out the advertising space (for around $1.5k per day).
This would imply that these leads need to be worth at least $1500/264 = $5.68 per lead. Does this look like too much to anyone else? I would have guessed that independently of what they're selling, the conversion rate has to be attrocious, as people signed-up not because of their interest for the thing being sold but because they wanted a free car.
Maybe the reason why this works is that people who are stupid enough to give out their names on a mall promotion, are probably also easy to push shit on.
EDIT: I forgot to add at least two other costs: they need to lease the car, and they need to pay employees to keep an eye on everything. So that figure is more of a lower bound.