I had to shake my head when your original request was for a quality battery for cheap. Like a Provari, you often get what you pay for, and you usually have to pay a little more for quality regardless of what it is. These batteries that we use in our mods pack a lot of stored energy, and in a sense they are an accident waiting to happen. No battery is completely safe. Some are safer than others.
I see people on ECF bragging about the deals that they "found" on Ebay or Fastech. Cheap no-name batteries of questionable quality with a dubiously high mAh rating. Buying batteries that should never be used in a mod. Sound familiar?
People need to educate themselves on which batteries to buy for the application in which they will be used. I'll never forget the guy who was using a new mod. He had just received it after the B&M vendor had built his new RBA with a sub ohm coil. The kid had no idea what he had or what he was doing. He promptly destroyed two hot springs and wondered why his power switch was so hot. He was lucky that he didn't have a more serious incident. This was so wrong on so many different levels.
The number one priority for choosing a battery IMO should be safety, and then safety. This is why I no longer use protected batteries. Within a month of receiving my first mod using Trustfire protected batteries, I had one vent violently and almost cause a fire. Since that incident I did more research and now use only IMR safe chemistry batteries in both my mechanical and regulated mods. For over a year I've had no problems using AW IMR batteries in both my mechanical or regulated mods.