The other day my wife saw a sweatshirt she really liked on sale.
She grabbed it and a few other things for our kiddo at the same time.
But when it came time to ship, it turned out that the sweatshirt wasn't in stock and the order was shipped without it.
She ended up not getting the thing she really wanted (the motivating product) and only got the other things that she was lukewarm about.
The problem turned out to be from poor inventory tracking. The store was selling products they didn't have and couldn't get.
These stockout events have become more common this year and rightly so, are upsetting to customers.
They are especially a problem when the primary product a customer is ordering becomes unavailable.
That causes the customer to regret the entire purchase and lose trust in your store. Often to the point of going elsewhere for every other future purchase (and maybe telling their friends).
Now more than ever is the time to be keeping an eye on your inventory counts. Be extra careful with product you can't easily resupply. And if you do need to refund a customer for an out-of-stock product, make it part of your customer support process to see if the customer has an alternative or they want to cancel the order.
If you do have inventory, one easy way to earn more traffic and sales is to use Google's Rich Results.
Using an app like JSON-LD for SEO will let Google show your availability directly in the search results. That'll help attract customers who are searching for a specific product.
It works similarly in Pinterest and Bing.
Setup is easy too, as JSON-LD for SEO will automatically install its code once you authorize it.