An important thing to note when buying a car that includes subscription services is exactly what those subscriptions are for.

For example if the maps, traffic info, alerts, etc depend on a subscription there are couple ways it can go.

1. The subscription is actually for that data and the alert services. The car's systems only accepts those sources and so if you do not subscribe when the trial ends those stop working.

2. The data and services can be accessed on the internet for no cost (you made need a free account with the car maker's site). The subscription is for cellular internet service for the car.

In case #2 it might be that the car is only capable of using that cellular connection for internet access and so you will need to subscribe if you want things to keep working.

Some cars however can use a WiFi connection instead of their cellular connection for internet access. If your phone includes a WiFi hotspot you may be able to set the car to use that and then maps, traffic, and alerts might keep working without needing a subscription.

Also many cars will let you update data by downloading it on your computer and putting it on a USB drive and then uploading to the car from the US drive. You won't get traffic info and alerts that way, but at least you can keep maps from becoming obsolete.

Having recently bought a new car after last buying a car at the end of 2005, dealing with subscriptions was by far the most annoying change since the last time. Just getting information on what depending on subscriptions and what my options were if I didn't keep the subscription was a pain for nearly every car.