Stop in for a cup of coffee

So question for the group, especially the northern group. I’m wanting to heat my little yard barn this winter, 12x28. I want something safe so I’m trying to stay away from el cheapo space heaters. But a permanent unit is way out of budget range for this idea. Anyone have any suggestions on a safe way to heat it?

I have a forced air house furnace in my shop. Works awesome. Otherwise o know guys up there that pick up the 60-80k BTU hanging ones at the home supply type box stores. Work great..