You know, I never even thought of that! OMG.
Yes, propane can be expensive. You just have to shop around and get the right supplier. I have had three different ones before I found one I liked and was reasonable. Natural gas is not an option for me nor would I want it (BOOM!).
Why are you worried about a natural-gas BOOM but not a propane BOOM?
Has been proven to be safe....and has been safe for many years.
It's an abundant gas...and cheap.
And to top it off....the United States has LOT's of it.
My family has had NG as a fuel for more than 30 years. I've used it solely for more than 10 as a heat/hot water source. It's no more, or less, dangerous than propane.