What do you feed a baby sparrow that is easy to get because I have no way if getting to a store soon and it is hungry?

If you have access to any worms, or can find any, chop these up into small pieces and feed these to the sparrow. If it doesn't open it's mouth, try tapping it's beak to encourage it. If you own a cat or dog, you can try soaking cat or dog food in water until it is mushy, and feeding this to the bird. As soon as you can, go down to your nearest vet or pet shop and buy a baby bird formula or appropriate vitamins.