Many online retailers provide THC vape pens for sale. It is advised to buy a vape pen in the USA directly from a reliable company's website (Ubercann), which provides vape pens that have been evaluated and approved by independent laboratories. There are many brands available, and each has a unique mix of benefits and drawbacks. Make sure the company will be there for a long enough period of time when choosing your vape pens so that you can get replacement parts from them.