Extras
The goal of any business is to engage users multiple times: acquire them once, then re-market to them to generate lifetime value, via email marketing, promotions, SMS campaigns and similar.
LTV and post-sale revenue are important parts of your profit bidding and margin calculation. If a new customer is worth more to you than their first order, you can afford to pay a little more to win them.
How to work out your LTV
We recommend you look at your web sales and see how many orders were generated directly from advertising online. Then look at what additional sales these customers made, and the revenue generated. Divide this extra revenue by the number of customers to work out your average LTV per customer.
Example
Tip: to stay on the safe side, use the profit those repeat orders made, not the full revenue. At a 40% margin, £18.00 of repeat revenue is £7.20 of lifetime value.
In time we recommend that you refine this LTV down to product groups.