SumoMe offers software products for advertisers to automate your site growth. They offer tools that help to increase your traffic and eventually get more customers. SumoMe used this free trial email sequence to promote the feature: List Builder.
SumoMe opens with an optin page where you can subscribe for a free trial of List Builder 3. Followed by some instruction emails. After that they emphasize the benefits of List Builder and introduce other SumoMe tools like HeatMaps. At the end they try to persuade the subscribers to buy SumoMe Pro, to get Pro access to all their tools.
You can read more about List Builder and other SumoMe tools here: https://sumo.com/