Well I've been looking online for this type of usb charger at local stores (like, wal-mart, radioshack, and bestbuy) and found a few things but, I don't know how reliable they will be. So my questions are, which ones from these stores would be the most reliable to vape at 5v (manual PT)? I did do some research on this topic but there were so many opinions and don't know where to buy? Or should I just buy online? Just looking for a quick resource but if the net is better I'll settle for that. Thank you!