[nytopop]

You can purchase mass produced stuff but the quality of vape you get is much better with DIY setups, though it puts the onus of safe design parameters on the builder. With electronically regulated devices this risk goes down a great deal, older gen (though still in wide use) devices called mechanical mods would basically short circuit a lithium battery to a coil of wire - if the resistance is too low you pull way too much power for the battery and catastrophic heating occurs.