I came accross some small drums that work pretty good for me;
one is a 15 gallon chemical drum, that I got from an agricultural fertilizer store, it is round, with 2 threaded openings on top- one, a 2" pipe thread; the other is 3/4" pipe thread, perfect for a drum pump, and vent, if needed.
The other also has a capacity of about 15 gallons, but is rectangular shaped. This one also has two threaded openings, both are 2"- one pipe thread, the other has very coarse (large) threads, but the bung, (plug), has a knockout built into it that is 3/4" pipe threads.
They are both white transloucent plastic, very strong, well built. Easy to move, filled, or empty. Paid a "deposit" of $10.00 for the chemical drum, the soap drum was a freebie, and my source told me that some of the soap drums they handle are for "one time soap use",the dealer doesn't want them back, Also available in 35, and 55 gallon sizes, this is the liquid soap they sell to car, and truck washes, so check with those places if interested.
HEADS UP!
Be sure to thouroghly clean them, and store out of sunlight, after 4 years of use, being in the sun, one of my soap drums cracked open when I moved it. Thankfully it was only about 1/4 filled. My other soap drum that I contain used motor oil also has some "sun cracks" in it so I'll be carrying it to the recycler to empty it, then replacing both.