It says -1 gold a little farther up. I am not sure where to post the ss though. I just tested it as well, and I didn't need any gold to buy a bunch of ngacha(they still call it that in the shop, so guess I will stick with it).
The question now is whether it is a bug that it says it costs 1 gold, or whether it doesn't draw any gold when you buy. Perhaps it is time to stack up on ngacha.
I used up all my SR-gacha as well. s
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ahh, I have acquired the ability to upload images.