Please note that the 30 soul crystal you receive you can use again to claim more rewards, which you can use again to claim even more etc.So this event is actually:
Spend 100 soul crystals, and receive 142k gold, 142k daru, 1.4 x lvl 1-5 gem pack and 43 soul crystals.
100 SC worth 50 balens.142k gold worth 3 balens, 1.4 lvl 1-5 gem pack worth about 7 balens, 43 SC worth 21 balens (daru worth nothing). So by using a goodie worth 50 balens, you get a bonus pack of 31 balens. More than 50% bonus! A really great offer, you should spend all your SC. And don't worry about not getting mahra, mahra is overpriced anyway.
pack1: 33*+25+2=60 balens (6% discount)**
pack2: 33+100+4+60(prev. pack)=197 balens (9.8% discount)
pack3: 66+1000+8+197(previous)=1271 balens (25% discount)
*see Father's love value explained here
**prices calculated using this guide
Looks like if you want to get some reasonable discount, you need to spend 5000 balens. And that's with me valuing sepulcrum to 10 balens (will make an entire article just about sepulcrum soon).
Now let's see if there is something worthwhile to buy.
First, if you saved up your horns from sky trial, and think you should spend balens to get more will crystals, this can be the good time.
Buying fashion core for 270 balens apiece is a decent deal too since cloth synthesis.
If your fate is not maxed out, you can spend balens to reach chest2 and maybe chest3.
There is also on sale Poseideon's wing, a class A wing for 1726 balens. Unless this wing is essential to upgrade your wing by 1 level in the near future, this deal doesn't worth it: the stamina itself you get after identify worth only 400 balens (8x5 endurance: 40 BR)
And don't even think about buying soul crystal packs!
