Not sure how many you're needing, but I've used Nexar in the past, which some of their models have front and rear cameras, GPS tracking (which can also show speed), etc. If you're just wanting a dash cam and no telematics, I would check them out.

If you're wanting some telematics, in addition to the camera itself, I'd recommend checking out SureCam and/or Samsara.

https://www.lytx.com/surfsight/surfsight-solutions is who we use.

We use SureCam. Ours are only forward facing but I know they have both. Price is very reasonable compared to some other vendors and any severe alerts automatically get uploaded. That was the main reason we went with them. You can also go in and request footage as well, if needed. We purchased our cameras but you can also lease them which gives you the benefit of updated cameras when they come out. As for the cost per month not sure what it is for dual facing but for the forward facing it is very inexpensive and as Drew mentioned, we get some telematics. For example with the forward facing I can get speeding alerts and it gives alerts for harsh braking, acceleration and cornering. The alerts are not perfect but I'm guessing none are. We still get alerts when they are in a lot filled with potholes and it rocks the vehicle or they enter a parking lot with a bit of a lip going in.