When I got a new can of propane, for my torch, it was $9. At wally world, it was $4. Then, when I went to get a can of cooking stove propane from the camping department (at wal-mart), I notice that the tank was $3. After getting home, I noticed that the threads were exactly the same, and that the torch head would screw onto the neck of the "camp propane" bottle. So, as anyone would do, I fired it up, and it worked! Of course, it would shut off it you tilted it too far, but what the heck! $3 for a can of propane. But then I thought "Why is this so cheap, and why haven't I heard of this before? Is ther something wrong with this? Will I blow myself up?!?!?! Anyway, I'm all for saving $2, or $6 (depending on where I go), so is this actually a reasonable way of saving money?So what I'm asking:-Is this way safe? I haven't fired it up since, in case it did something bad.-Why is it so cheap to but it that way, and so expensive to buy regular tanks?-Has anyone else done this?If anyone can help, it'd be appreciated.