Retail cost of the scooters is ~$600. They're probably getting a discount but I doubt it's 50%. No idea about the actual ride volume. Not that this changes your numbers that much, but just adding some context.
I got a Xiaomi scooter for $305 directly from them as part of a 10 scooter order (including shipping costs). Bird and Lyft both use these exact scooters. I'm sure they are getting a better deal than I did, but the tariffs have since kicked in so $300 is probably right on the money.