Not to me anyway, it really doesn't make sense. They are two words you would not use together in what I (still) call proper English.

In my opinion this would be the closest...

I'm fairly sure it's simply a cheap/low quality brand.

A commodity brand is one that has few or no features that distinguish it from other similar offerings. In fact, a commodity is virtually the opposite of a brand – since a strong brand is built around a unique differentiation. Good brands make a unique promise – and deliver on that one-of-a-kind differentiation. As Seth Godin wrote in his book “Purple Cow,” a low price strategy is the last resort of a marketer that is out of great ideas. Brand commoditization is all about failing to invest in a brand’s unique differentiation, which forces companies to rely on a low price strategy.

A brand is commoditized when it is not offering enough value for customers to pay its asking price. This lack of value may be the result of company executives so busy with day-to-day business that they lose control of their brand, like a child left to raise itself. Some may simply forget to reinforce their brand’s differentiation at every opportunity. Or, commoditization may come from trying to be all things to all people or attempting to match the competition’s every offering – losing sight of the unique promise on which the brand is built.

In effect, commodity brands set themselves up to be the victims of their own lack of self-value. Eventually, key differences with competitors’ brands are erased. Brand loyalty is based on the idea that a brand is uniquely better and different, not cheaper.

http://www.greenemarketing.com/bytes_brand-bland.html

As opposed to, say, "aspirational brands".



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Note added at 1 hr (2007-04-11 16:11:48 GMT)
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Sometimes, a brand, that has a following among some population groups. Akin to "household name". For example, it runs in some American families or even towns to "always buy Ford". This is one indication of a "commodity brand".

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Note added at 1 hr (2007-04-11 16:14:53 GMT)
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Another meaning is "a brand for a product sold/traded as commodity": any brand of gasoline, for example, is a commodity brand.