Because it uses Amazon's pricing and built-in shipping.
Buy with Prime pricing can vary from ours as it reflects Amazon's pricing, which uses built-in shipping for your item. Our website (wyze.com) does not use built-in shipping, so the shipping charge is separated out and the price may reflect our own discounts and offers, including Cam Plus member pricing.
When checking out using Buy with Prime, you're getting Amazon's price and the shipping charge will show as $0.00.