Hi, and welcome to the ECF.
That would be a working e-cig, with the addition of some
e-liquid. You'd have to drip directly into the atomizer after every few drags to vape on that. You don't need cartridges, but they would be better than dripping if you want to vape while driving or other such situations where it would be difficult/dangerous to drip. Atomizers often come with a cartridge without filler, which can be used instead of a drip tip, but it has to be pulled out to drip in, then replaced.
In my opinion, it would be a problematic setup for the average person, though. 510
batteries don't hold a charge for long, and you'd have to charge it on a USB port, unless you included an ac-dc wall outlet adapter with the charger. Atomizers need to be cleaned to get them to last very long. It's advisable to have at least two
batteries and atomizers, which is why most starter kits include that.
Generally, starter kits will be less expensive than the sum of the prices of the individual parts, so if you can afford it, they are a better deal most places.
So, what are you looking to get out of your purchase? Are you just looking for something to try, or are you just looking for a setup for light use at home?