Searching for a commodity

 I have an idea in mind with regards to optionality trading. But besides oil, I can't seem to find similar products that work in the same way.

The criteria are as follows

• The physical commodity prices off a transparent exchange on a regular basis (i.e the price of the commodity can fluctuate everyday but there should be a fixed/closing price at regular intervals that is recognised by market players)
• There is a paper market that follows this price movement
• Preferably, this commodity can be stored
• Preferably this commodity's absolute value is low (to make financing the purchase easier)

Thanks in advance. You can comment on this post or drop me an email at ntuchartist@hotmail.com