The mechanics of a natural gas barbecue are more complex than a propane barbecue, which means a slightly higher price tag. In the end, the money you save using natural gas compared to propane will more than outweigh the initial outlay.
Natural gas is much cheaper than propane. Even when you consider the cost of installing a natural gas hook-up in the backyard, it will be less expensive in the long run.
Yes, you can change your mind. Call a retailer who specializes in grills and they can advise you on converting your propane grill to natural gas.
Every natural gas grill comes with a connection to the gas supply and an on/off valve that is separate from your grill. Any time you want, you can turn the valve and the gas is out.
Speak to the manager at the propane filling station and see if they can safely disposed of the tanks.