Dallas here from the Social Care Team at Shopify.
There's absolutely a way for you to do that if you're wanting to offer your customers a free product. The best option that I can suggest is to use an app like Free Gifts by Seccomap. In addition to offering a variety of gifts to your customers, they have a lot of other deals and "sales" that you can offer visitors.
There isn't a way to do this directly on the Shopify platform, but I think if you were to use an app like the one I gave above or even one like Freebies or Bold Sales Motivator then you'd really get what you're wanting.
Since you are looking to offer free products for particular customers another thing that might be of interest to you is offering a loyalty program. A loyalty program would offer different features and deals to certain customers, but it also would work for referral and rewards. One of my personal favorites for this would be an app like Loyalty Lion. It is one of the most trusted programs when it comes to loyalty programs on the Shopify platform. Smile.io is another one that I have personal experience with.
This's a blog post that goes into more details about what some major stores have done when it comes to loyalty programs. The Starbucks and the Sephora loyalty programs I know are extremely successful.
This blog post goes into even more detail on the technical aspects of how you can make sales and how loyalty programs work for you. The best part is they even statistics for all of them.
I hope this helps to answer your original question, while also giving you some more information about how you can make these programs work for you to increase conversion and make more sales.
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The user journey is: 1st time through checkout fill in form details and check the "Keep me up to date" button. Result: customer account created with 'Accept email marketing = yes' 2nd time through checkout as the same customer and the "Keep me up to date" button is pre-checked, recognising the 'Accepts email marketing' flag. IF THE BUTTON IS THEN UNCHECKED....I would expect the 'Accepts email marketing' flag to be removed but this is NOT happening. The customer account is still showing as 'Accepts email marketing' I presume unchecking this box should update preferences - can a Shopify Expert please confirm, and advise how to investigate this further?
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