Lux Investing - Is it possible to buy £500 worth of a commodity using a similar process as share investing?

Is it possible to buy £500 worth of a commodity using a similar process as share investing?

I should have put this in the question but I was specifically referring to making an online investment.

I don't know about Great Britain, and I don't know the exact lower limit for setting up a trading account in the U.S, but there is no dearth of commodity brokers out there who will be happy to let you trade. Try a web search on "online commodities trading" But commodities trading is NOT an investment. Think _gamble_.