Shipping 1 or 100 buyer pays same amount?!

[saltyheifer]

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.  

[eason_feng]