In more ways than donating a prize. They can underwrite your costs, put their name on the headline prize, match sales during a set window, promote your raffle at the counter or encourage their staff to sell tickets.
A specific ask matched to the business, what they'll get in return and a clear next step. A tailored ask beats a generic sponsorship letter every time.
Your raffle permit conditions. Some rules affect how prizes, sponsors and promotions can be presented, so confirm them first.