I price compare as well before any purchase including factoring in shipping costs. Usually I can find single item purchases cheaper elsewhere. But if I can save a few bucks on the bottom line, why not?
With that said, I'm a sucker for kits:
I. While ultimately the kit itself may only be a $5.00 savings from the normal QVC price:
1) that's still $5.00 kept in my pocket (and money is money)
2) another $5.00 kept in my pocket for each subsequent shipment if I elect to buy on AD
3) adding the retail value for each item contained in the kit, the consumer is still way ahead of the game on the overall total value of the kit. (But in my decision making process, I look at the individual cost per item of the items in the kit I actually want, do that math and then decide if I want to pull the trigger on the purchase of the kit.)