Good explanation of Robinhood's business model by Matt Levine: https://www.bloomberg.com/opinion/articles/2018-10-16/carl-i...

And by Evan https://medium.com/automation-generation/commission-free-tra...

I know Robinhood makes hundreds of millions with this, do you know how large the full market actually is?

Which is a nice way of saying you're in a pool of bait for high frequency traders.

...but that's really not so bad. Having an algorithm skim 2 cents/share off of you is a lot better than paying $5+ per trade (assuming you're not trading 1000s of shares, and you're not in penny stocks or options where spreads are big).

It's not a nice way of saying that, the "pool of bait" logic is totally wrong. There's a lot of nonsense written about high frequency trading on the internet, but for example Matt Levine's explanations are completely readable, correct, and on point (see the other comment).

If someone will pay to trade with you instead of someone else, you're definitely not getting the best price.

There is no free lunch... To paraphrase a friend from high school: "...when you start to play and don't know who the patsy is, usually it's you..." ;-)