It happened to me and it was because I bought directly at Market price from my credit card. It's better to buy USDT with your cash, and then with that balance buy $BTC directly from spot.

I bought 100 reais of BTC when it was at 80 thousand, but the average cost ended up being 92 thousand, how to understand this.

I bought during this last dip now

can someone explain this to me ??