i spent a few months searching, because they are quite large, i wanted to find some fairly close to me becuase i don't have a truck..
i've seen them on craigslist from $40 up to $150 - most were a couple hours from where i live..
when i found them for $40 they happened to be about an hour from my house so i rented a truck.. all told, 4 totes (2x275gal and 2x330gal) ran me almost 260 to my door.. probably could have built a big gb for close to that

the guy i bought them from is starting a company reclaiming used oil for biodiesel..
some landscaping companies buy dye in them for mulch, the dye is food safe so ok for re-use..
a quick look at terra haute cr showed me this;

http://terrehaute.craigslist.org/grd/2668555476.html
a good cleaning with power washer and detergent, bleach rinse should clean them up.. you can always test by putting some water in them and leaving in the sun.. if you get algae growing you should be ok (i found a couple blue barrels with warning labels, cleaned and put some water in to check.. when i found that mosquito larvae were doing quite well, i decided that the barrels were "probably ok"..