I does and it doesn't, I try to wait for sales if I can, so it doesn't always happen. But sometimes I get it on sale and than there's a better sale later, and this point it's less bothersome. At least for Edenfantasy that's how it happens.
I was really frustrated when I got a candy mold from Amazon, before mine even shipped the price dropped. Not even a sale, the price dropped $3 for good. I contacted them and asked if I could get a partial refund, customer service somewhat rudely pointed me to the FAQ that says "No". While the price drop encourages me to get a second mold for crafts, the customer service kinda ticked me off so I'm holding off on another purchase.