when buying a vape do you just buy the vape or do you need to buy other equipment for it as well?
Not really sure what your asking here, there may be a terminology / language difference. I'm not sure what items you are referring to when you say "buying a vape"
When I vape, when I am in the act of vaping. I need a "mod" (with power), a tank/atomizer system, and juice.
Mods
The mod can be a mechanical mod or a regulated mod. Mechanical mods have a battery and a button triggering the battery. Regulated mod have a battery, the button, and additional smarts. Common features of the additional smarts are to ensure constant voltage being applied to the atomizer, perhaps allow the user to adjust voltage or wattage (VV/VW variable voltage / variable wattage mods), perhaps saftety features to prevent over draining the battery or allowing the the battery to continuously drain if the button was stuck shut....
Atomizer / Tank
The coil to heat the juice, wick, and the juice holder is in the atomizer / tank section. There are several kinds including clearomizers, cartomizers, and rebuildable systems. Some types known as drippers (which can be rebuilt) only hold enough juice to saturate the wick and you drip before you vape right onto the wick and coil. Tanks hold more juice, and with cartomizers you have wicking material stuffed in a cylinder called a carto to hold more juice.
Example Set Up
An example decent set up with be an innokin mvp 2.0 (regulated vv/vwmod), a Kanger Aerotank clearomizer tank, and some juice perhaps from nicoticket. More cigalike settups include evod's and spinner type batteries and matching mini tanks which can be clearomizers or cartomizers...
Other Stuff
The MVP's battery is built in but many mod's allow the user to change the battery.... which adds the need for rechargeable batteries (make sure you use ones for vaping, many types can be dangerous) and chargers. Rebuildable tanks add the need for coil building gear, wicking material, some tools. A way to check resistance and voltage is a common tool for the trad and a must have for rebuildables. Nonrebuildable clearomizers need their heads replaced, so more atomizer heads for them......