I have just connected my car to the hotspot and set up a free account managed by
https://www.hotspotdrive.com, data supplied by T mobile from Germany: It says
Drive Start +: Contract duration 1 month
Can be cancelled monthly
1 GB of data volume each month
1 month free trial
11.00 GBP per month after free trial
Learn more and buy
You have to buy the contract on the next page with your card or PayPal.
So, there is no automatic contract. In the meantime it is still giving free internet. Time would tell
The contract is £11/month for 11 GB of internet on a monthly rolling contract that can be cancelled latest 6 days before the end of the month