You can recharge or sell props, cards, clothing at the trading site...

You can also make a wish in the wishing well, but the possibility of winning the coupon is very low, so it is not recommended. You can go to strong cards and then sell them to earn coupons. A 5-star card can be sold for 100↑ coupons in my area.

However, if you use modifiers, your account will be banned. You need to think clearly before doing this!