Specifications for Free Gacha and Coin Gacha

I'm truly grateful for the daily free gacha. While the free gacha is fine, could you please add a purchase confirmation for gacha that consumes coins? I've wasted coins multiple times by mistake. The items aren't particularly good deals either, making me feel like there's little value in pulling anything except the free gacha. I keep getting duplicate avatar frames too. I hope duplicate avatar frames can be exchanged for coins or stamina.