I'm developing a channel that could have many new products each month. Currently I create each product manually using the Roku Developer Dashboard -> Manage My In-Channel Products.
Once we're in production, this may be impractical. Having people manually enter each new product would be time-consuming and worse, error-prone. Users would be unable to purchase a product if the product identifier in the Channel Store, didn't match the product identifier contained in the RSS feed that has the product descriptions.
Instead of creating a Roku in-channel product for each unique item, you could create one at each price point. For instance, a $2.99 TVOD rental can be one product. Then you use your own server to track which title was purchased.