Day 4 - Related products with a bundle offer
Sending just a product is not enough. Give them a reason to buy. Send 2-3 products together and make a discounted bundle offer. You don't lose anything as remarketing consumers will not cost you anything. An amount of money you include in your margin for advertising expenses may be offered as a discount.
For instance, if your expenses on Facebook ads are 30%, you may offer a 20-25% discount and your margin will still be increased.