We have two vehicles, one with full coverage, one with liability only (but both with roadside assistance). We pay $290/6months, which breaks down to around $24/month per vehicle. And that also covers an extended warranty through them called mechanical breakdown insurance that is a 100K/10 year coverage one the one full coverage car (yes, extended warranties are bad, but I did the math and it's just about $400 for the life of the coverage and I like the odds for that price). And that's through GEICO too.
I imagine if I dropped the full coverage and mechanical breakdown coverage on that one vehicle we'd be well below $25 per car.
One of the things that really reduced our rates was to get them to run our insurance through a subsidiary called GEICO County Mutual instead of regular GEICO (and this was not something they automatically tell you about - it took two different agents to hit on one that brought the county mutual option). The only disadvantage was they don't have accident forgiveness, but that isn't something we care about, so it was a no-brainer to switch. This apparently isn't available in all states, tho. But that coupled with us getting the multi-vehicle and homeowner's discounts reduced it by a substantial amount from what I used to pay.