1. Visiting to ESPN+ website.
2. Hit the 'ESPN Plus' button.
3. Enter all your details.
4. Put in Payment details and click the 'Buy ESPN Plus' button.

Unluckily, ESPN+ is not offering any ESPN+ free trial, but you can avail discounts on existing plans. Upon signing up you can enjoy first month on ESPN+ at discounted price. Also, get a year long subscription with a discount of $14 with Annual Plan subscription.