I'm still not convinced that opening the packs is a good idea. If you do it for the money, holding the packs and selling them after the general sale for CL is over would be way more profitable. I'm also sitting on a heap of potions but I don't think I am going to use them.

When the first presale ended, I made the mistake to buy some legendaries that fitted my playstyle like Djinn Biljka. That card is currently sold for around 10% of the price that I payed back then. I recently bought a maxed out Pelacor Conjurer, Mercenary and Deceiver (three of the best current reward cards if you are on a budget) at around 20$ each.
I'm sure that the airdropped legendaries will also fall severely in price during the coming weeks.
In my opinion it is way cheaper to buy the cards you need from the market than opening the packs on your own.
You will receive a lot of cards that you don't need or get unfinished upgrades.