i think that people mostly buy is gadget or console also games and voucher. i dont feel like they want to buy food from the online shop because of the shipping times maybe take too long, so they would go to shop nearby.
my recommend for the shop is selling online goods like voucher cause that is more efficient for shipping time.
You are completely thinking to buy all the products available in Ecommerce site. It means purse.io would be the best option to you, you can buy the brought via purse in amazon.
you can get credits points with your purchase and it increase as your number of purchases increase.