It's quite hard to get numbers.
Firstly the reported trading volumes are about 95% fake. https://www.forbes.com/sites/cbovaird/2019/03/22/95-of-repor...
Then much of the thing buying is illegal stuff like drugs that doesn't get well reported. Wikipedia has "A reviewed 2013 analysis put the Silk Road grossing $300,000 a day, extrapolating to over $100 million over a year."
Coinmarketcap has daily crypto volume at $43bn a day
so say 5% is real that's $2.1 bn/day trading
and say drugs trade etc is $1m a day, that's a small proportion.
comission on those trades is probably about 0.2%*2.1bn= $4m/day
Regular retail business, not much https://news.ycombinator.com/item?id=19280689