Raffle315 allows each participant to purchase up to one product. There is no feature to set the purchase limit for each winner, such as “up to 1 item” or “up to 2 items.”
As an alternative, you can use an app that allows you to create bundle products, create a bundle containing multiple units of the same product, and make that bundle the raffle item. However, in this case, the winner can purchase only the “bundle product,” so customers cannot choose the number of items they want to purchase.