I took my 250 gallon tank I found and cut 26 inches out and welded the cap back on.. Put a 24 inch pipe firebox on it, dang thing works great! You could do the same with that, just use the leftover tank for firebox. Mine ended up being 171 gallons, plenty big enough for home use.
What is the diameter and length of the 500 gallon tank? Not knowing those numbers if the tank is long and skinny cutting it in half and making two 250 gallon smokers is a good idea....if it's fat and short it would make a nice rotisserie......a big one at that.
If it is too big for a smoker, and no shame in that, you could always cut off the bells and use them for a fire pit or really big cooking wok. Send the rest of the tank in for scrap and it will pay back some of your expense.
He got the tank for a $100. I didn’t measure it. I looked it up and 500Gs are supposed to be 36-40” diam, 10-12ft long. That seemed about right. I’d call it a standard size tank. The end bells aren’t dished, they are pretty close to hemispheres.
I saw a pic where someone took half of one, and made a vertical and had the end bell on the bottom. A vertical with 2 or 3 36” shelves would be ok. But I’d like to be able to cook a pig it it.