I’m not from there (just reading Fargo-Moorhead makes me chuckle, with all due respect) but I’d suggest looking for a welding supply store. That’s where I go. $15 to swap a 5lb tank.
google “airgas” and see how close they are to you. that’s who I use.
Fire extinguisher shops have been less expensive than the welding shops in my experience.http://www.bing.com/maps/default.aspx?q ... U0ODMzOTg0
Ask these cats.http://www.prairiehomebrewers.org/