If you select this option during checkout, your order will be shipped at the lowest available USPS rate. Orders under 16 ounces (most orders) will default to First Class shipping and orders over 16 ounces will be shipped via Priority Mail. First Class packages generally take 2-5 days to arrive once shipped; Priority Mail usually takes 1-3 days. You will receive an e-mail with tracking information once we ship your order.