If you want to diy it, Check out ray Ozzie's recent project featured here on HN recently. Very reasonable priced with one up front payment for (10 ?) years of connectivity
Iceland: https://blues.io/blog/vacation-gps-asset-tracker/
Full Asset Tracking Project: https://www.hackster.io/paige-niedringhaus/low-code-gps-asse...
Adapting this for a car would be straightforward.
I've got a couple of the units and can say they are working well and very easy to interface with.
Here’s a pic of the note card plugged into their Raspberry Pi note carrier. That’s a standard 40 pin 0.1” spacing connector on the left, so it’s 2” plus the mounting holes in that dimension. 65x57mm and about 20mm tall for the stackable 40 pin socket+pins.