I sell candles. I’m new to Shopify. So if I sell 1 candle the shipping cost comes out the same for buyer if I sell them 50 candles?! What am I missing? I see nowhere to even put how much each candle weight or how many candles I can fit in a usps priority box! I’m going yo get screwed on shipping if someone buys more than I can actually fit in the box!! I’m so aggravated.