Vanguard gas heaters are powered by either natural gas or propane. Some models have the option of either gas type, but other models only run on one gas type.
The Vantage Hearth Blue Flame VSH30T is one option that runs on either natural gas or propane gas. This model is also available with a blower kit and is priced at $399 at Fine's Gas as of 2015. It has two different heating options, a wall mount kit and floor stand. There is no electricity needed to run these heaters, so they are perfect for emergency heat if the power goes out.