Hello abceliquid,

Yes, inventory is only available on the Plus subscription. This feature offers basic quantity-on-hand tracking and reporting features.

Here's how to turn on:

1. Click the Gear icon on the upper right.
2. Select Account and Settings.
3. Click Sales on the left menu.
4. In the Product and services section, click the pencil icon on the right.
5. Place a check mark beside Show Product/Service column on sales forms, Track quantity and price/rate and Track stock quantity on hand.
6. Click Save.
7. Click Done. 

Next, add products and services in QuickBooks Online (QBO).

Here's how:

1. Click the Gear icon.
2. Select Product and Services.
3. Click the Add a product or service tab.
4. Select an inventory type.
5. Fill in the necessary information.
6. Click Save and close.

You might also want to check this article for additional information: How to create and use a product and services list.

 Let me know if you have any other questions. I'll be right here to assist you.