One perk you can give your best and repeat customers is early access to new products.
You don't have to discount them so they won't cost you much to promote and they can come with built-in scarcity factors that don't try to trick people.
While it's difficult in Shopify to hide products from everyone, you can still create products and send links to them to your best customers. Tell them to only share the links with their best friends and you'll get some sharing ("shhh, it's a secret").
Ideally you'll use a limited-time access, say give them 14 days of early access before it's accessible to everyone else and/or limit the quantities you offer in this early access.
A rough version of this doesn't even need an app.
- Create a new collection for those early releases
- Create new products for these collections with some copywriting about the early access
- Make sure that collection isn't listed or included in public pages (e.g. "New products" on your homepage). Some themes might not allow it or it could be tricky so you might need to test it and talk with your theme developer.
Then send direct product links to your customers using email, social DMs, etc.
Once you get it to work, you should be able to use that early/exclusive access idea in future deals.
This won't cost any money to setup, just a bit of thought and time. It'll help your customers feel valued and special, and you could get some additional orders from it (true time and unit scarcity is powerful).
Which customers you offer this too will depend on your customers, how large your audience is, and how many products you have available. I'd recommend starting with the higher Frequency and Monetary segments in Repeat Customer Insights like the Whale, High AOV, VIP, and Loyal segments. Recency won't matter as much with this type of offer.