It would have to be something that has continuous value for arbitrary smaller fractions, not only valuable as a whole.
Then all you are describing is the granularity for how something is sold. In the physical world, commodities have this property and most everything else sold does not. The individual components can be purchased individually but the value when you are buying generally comes from the fact that you are getting a complete product.
Or for instance, let's use an example from the physical world where I am buying equipment from NewEgg for a new mining rig. Say they don't have everything in stock. They bill me for each shipment. If they ship the mobo, chassis, RAM, psu, etc. -- but not the GPUs, I've paid for something that has essentially no value to me (as a mining operator).
Now instead if I buy a contract for 100,000 banner ad impressions of online advertising but I settle at the close of each day, the granularity is per impression. If I had 4,700 impressions for the day then I pay exactly 4.7% of the total contract.
I don't know of many virtual goods that have a granularity smaller than the unit in which they are commonly sold.
Do you have a use case where what you are describing is needed?