You think $100/mo for car insurance is expensive? The average car insurance rate is apparently $133, but I personally know it's not very hard to hit more than $100 (even on an older model car) if you want more than liability.
I'm nearly 40 and have been driving for decades. I recently downgraded to liability and it's still $55/mo for myself and my similarly aged significant other.
In my experience in the US, the cost of even essential coverage varies dramatically by zip code. For example, when I moved 1 mile from Cleveland Heights to Piedmont Ave in Oakland, CA, my rates went down by more than 20%.
So yea, significantly more expensive for poor people.
It's more expensive for people who haven't been continuously insured, who have had accidents, or who otherwise have a poor driving record. That's a larger fraction of poor people than it is of not-poor people, so yes, typically insurance is more expensive for poor people.
Liability-only insurance with minimum coverage for a good driver with a single car would be only $300-$400/year in my area. $1,200 is if you have collision and comprehensive
The cost varies dramatically from area to area though because each neighborhood has different loss risk, each state (and some locales) has different rules for underwriting, and different minimums for coverage.
