It's quite common in marketing to give consumers a free trial of a feature so that they can see what it has to offer. The goal is after trying the product the customer will be hooked and want to purchase it. That is exactly what Tesla is doing with their Autopilot feature which they are offering for free for one full month.
The technology that has been all the rage of late can be quite enticing for driver's who will get to see what the automotive community has been very excited about for the past year. The Autopilot feature costs $2500 to unlock when the car is first purchased but after the fact the consumer will pay $3000 to add the vehicle.
The marketing strategy hopes to convert car drivers to purchase the feature in which Tesla can make an extra $500 for each unlock on their vehicles.