Do you need app for goods arrival notifications?

[AndreyL]

Next idea: button is on product page, if this product is not available. User push the button and subscribe for this product. When product become available, subscribers give a message (by email, sms, messanger) about this. 

[Brie]

Hey, @AndreyL!

Yes, there are a number of back in stock notification apps that can set this up for you. You can view them all here, however I'd recommend Back in Stock: Customer Alerts, Back in Stock - Restock Alerts, or Back in Stock Product Alerts. Hope that helps!