That's basically gambling. It feels great when you do, but you usually won't. Market forces alone assure that it's nearly impossible for the average rare to be worth more than the average pack. Your LGS is not going to buy the average rare at the cost of a pack when they get literally thousands of packs at a discount before you can even buy one. When you open a single pack and hope to get something of value (to you) you're either trying to beat the system or attach a value to a card that goes beyond the dollars and cents of the market. And when you do beat the system, the buy price a store will offer you is not the sell price that everyone attaches to the cards as its "value."
This is a very long-winded way of saying "you should sell directly to other players, not via a buylist" :P ---
Nonsense. "Testing" is for when you're still guessing--and now, I have no need to guess. -- Agatha, Girl Genius