I have two MUST HAVE tools that have made us over $10,000.
First is: Fishbowl Apps (https://apps.shopify.com/fishbowl-prizes)
This allows you to host a giveaway on a marketplace, a simple offering of a $50 prize over 7 days got us 2500 emails.
Second is: Rare.io (https://apps.shopify.com/rare-io)
This is free for us because we don't have 20,000 emails yet but it has a nice drag and drop email builder along with analytics of our customer base. It also sends each customer a different email showing the product they're most likely to purchase next arriving in their inbox when they're most likely to shop on your store.
The combination of the two is perfect, one gets you emails the other gets them to buy!
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