Within Megaventory, you can mark whether a product is sellable or purchasable or not.

Here's how you can do it:

1. Start by navigating to the Menu and selecting the "Products and Services" section.

2. Click on "New Product/Service" to begin adding a new item.

3. You'll then be presented with options and features related to the product.

4. Choose the relevant settings according to your needs and preferences, and then check the respective toggle.

5. Additionally, you can customize the dates for when the product will be available for purchase or sale.

6. Don't forget to save your changes once you're done.

By following these steps, you can efficiently manage the sellable and purchasable status of your products.