I had a 100# tank (leased) at my house after I bought it. After a couple of years with only my stove using gas (which I had told the company when I leased it) they canceled my lease due to lack of volume of gas used and took their bottle back.
I purchased a new one at Home Depot. I took it to a local propane seller and had them purge and fill it. They do not have to weigh it, they measure the liquid quantity that goes in (just like pumping gas). I have 2 30's on my trailer and a new one for my work heater for the garage or 'tent' when I work on my truck outside in the winter. I think that I paid $80 for my 100#. Like was posted above, a welding supply, or True-Value type hardware store should have everything you need.
Good luck.
MikeH
