Now if only someone could do the math if it's profitable to buy 2x or 4x multipliers now while there is discount running instead of waiting for later. Common sense says: "no, it is not, it is better to buy 8x at once so that you don't increase prices too much for the next buy and not lose on bulk discount". But current discount is also rather large, so I am on the fence about it.
Buying 2 and 4 without discount costs: 173
Buying 8 without discount costs: 151, so it's 22 gems cheaper.

Buying 4 without discount: 113
Buying 4 with discount: 91, same 22 gems cheaper.

So what is better, to buy 4 now and be left with 2 gems without any next buys for a long time, or to keep current 93 gems and wait for 58 more to buy 8 without discount...

I guess I will leave decision for tomorrow.