It would be great if Wave could add a sales program which would allow one to record sales and then invoice from that program
Can you give us a bit more details on what you mean?
Are you imagining a point of sale system that feeds into your accounting page? We do have Checkout by Wave, which is currently in testing, which allows our users to receive payments without requiring invoices, but that is only currently available in Canada and the United States.
What in talking about is being able to enter a sales order which records against your inventory and thereby giving you a inventory balance to work with. You should be able to invoice from the sales order. You could then report on turnover and inventory availability.
Thanks for following up, @blackbaron.
Wave doesn't have an inventory management system. Wave is built with businesses that offer a service in mind, rather than businesses that sell products. This is why you won't find features like inventory management or purchase orders on Wave.
That isn't to say those features will never be added to Wave, but given that most of our users offer services and that we want to add features that benefit as many Wavers as possible, features like this have not been prioritized. We do suggest a workflow to handle inventory management on Wave, but it's very much a workaround. It might still help out, you can find it here.