Here in Pensacola Craigslist has some food grade ones pretty cheap every couple weeks. I bought a 120 gallon rubber maid stock tank and set it up in my garage to use as a holding tank for when I do water changes. I have a few small live rocks in it I add water and salt a day or so before then add a pump to keep it circulating and then the next day or so do a water change on my 90 gallon local tank.