Planted Tank Enthusiast
Join Date: Mar 2013
Location: Baltimore, Maryland
I've looked into this extensively, as Robert's Oxygen is rather pricey for just a tank swap.
For my 5lb tank, here are the ballpark prices. I don't remember their exact quotes.
Robert's Oxygen - Multiple Locations - Tank Swap - $20
Fire Line - Baltimore - Tank Refill - $18
Laurel Bottled Gas Co - Laurel - Tank Refill - $18
HK Fire Protection - Rockville - Tank Refill - $10
I recently moved from Silver Spring to Baltimore, and it sucks because HK Fire Protection had the friendliest staff and the lowest prices. If you're in that area, I definitely recommend it. Closer to baltimore, I usually go to Fire Line.