I buy at auctions. I have only gone to a couple storage auctions, not really my thing, but I do look for deals at any auction where I can flip for profit. I am almost always just looking for a double up minimum but as I start building an online store, I may delve more into volume, depending if its the right products. Often times my profits range from 300-1000% I do most of my auction purchases online through specific auction houses, which means I am paying ~20.6% on top of the settle price, so I have to make sure my margins are spot on. In the future I plan to expand solely into selling lots at auction houses, but that is some time in the future when I have the right things in place to make it happen.
I also participate in what I call real estate derivatives, which I will not elaborate on at the moment. Profits in that for me range anywhere from 5% to astronomical. For instance I am on the verge of flipping 2k into 100k on one deal. The downside on this investment strategy is it can take up to 3.5 years to see minimal to maximum profit, but I only invest money I can live without for that period of time. This is what a portion of my small business is based on foundation wise.
Of course I also day trade and purchase/ sell commodities from time to time.