How do people invest low amounts everyday into some index funds and not get eaten by fees?

I’m located in Europe and I use IBKR as my broker. Every time I buy shares of an ETF or stocks I pay certain fees. I’ve seen some guys that comment or post that they buy everyday 5, 10, 50, 100 USD of certain ETFs or stocks. My question is, wouldn’t you be paying a lot of fees, specially for those investing 5-10 USD everyday? Do you have brokers with no fees in the US perhaps?

Thanks.