Your lowest pack price matches the highest one you've recently paid. So, if you buy a $50 "special", you won't get any below $50 anymore. This is the main reason I am not buying those with BH gifts (they are over $10 and I refuse to cross over that threshold).
The good news is that there is a cure: patience. Do not buy at all, and after roughly a month and a half (maybe a bit less), the price should drop by one level (from $50 to $20 or from $20 to $10, if memory serves).
If you wait long enough, you can even get versions of normal offers at $5-$8 or so (slightly less stuff for 50% of the normal price at their lowest). These are the best value for money, but when you buy any of those, the offers go back to $10, and it's another long wait to get back. They are good for occasional spender, but - because of the wait needed - not for the regular ones. For those, I suggest to stick to $10 offers and not spend a cent more on any offer, no matter how much you like it or think you need it.