Will this "someone" be a vendor or a private sell? New or used?
The Mini Provari uses an AW imr 18350 battery (700 mAh), and with the extension cap can use the AW 18490 imr (11 mAh). Provape doesn't sell an extension cap to use an 18650 battery, but there are some third party vendors that do. Just visit the Provari sub-forums here to find where to find them.
ProVari
The Provari has a built-in atomizer resistance meter (when used, it will fire the coil to test it "under load", the most accurate way to measure its resistance) and battery volt meter (also fires under load). The fire button will blink when the battery needs to be replaced. Uses a standard 510 connector, using an ego delivery
device like a Kanger T3 will require an adaptor.
The Provari uses a single button for all of its functions. To get into the mode selection, you click the fire button 5 times. First mode is power up (Pu) to increase voltage, second mode is fire down (Pd) to lower voltage. Po can be used to turn the Provari off. Cb is the battery voltage meter. Ao is the resistance meter.
At some point you will want to pick up some antioxidant like Noaloxx to use on the battery endcap
threads to prevent them from locking up or interfere with battery conduction that can cause the Provari to shut down. This can be found at most hardware stores or in the accessory section on Provape.