I could only find a place that does exchanges and it was kind of expensive. $80 for the tank filled and 22 for swaps(refill) If anyone has any cheaper places Northern NJ please let me know!
paid $22 and change for a 20# swap... I gave them an old steel tank and got back a shiny almost new Carolina aluminum tank. I will be going to the fire extinguisher shop for a refills until the date expires.