Go to ft.com homepage, search for an article you wish to read & copy and paste it into Google News Search. If Google News has indexed the link it will show in the results and because you click through Google News it will take you to the full article whether you are registered with the FT site or not.
You can do this up to 5 times a day which is usually more than enough; commodity financial news can be found on a completely free site like bloomberg anyway, the FT's blog content (eg Alphaville) is mainly free & so it's the premium analysis that is all you need - The Lex Column, Martin Wolf, etc.
Also if you register your email address for a free account you'll get an additional 8 articles a month.