Ran across this excellent article from Gizmodo on sub-$50 earbuds, and the likelyhood that they are all pretty much manufactured by the same few factories in Asia using the same basic components. Essentially, pick a canned design, tweak it a little in the visuals department, slap a company logo on it, order a few thousand, and away you go.
Now, I'm an e-cigarette user, and this made me think of the state of that industry, as well. It's a well-known fact that a majority of the parts for e-cigarettes are manufactured by a small group of key Chinese manufacturers. These parts, just like the cheap earbuds in the Gizmodo article, aren't manufactured for quality or longevity, but for disposability and quick sales. If your battery on your e-cig breaks, just turn around and order a replacement for 15 bucks. Nevermind the fact that the new one will only last you a couple of months, they are banking on you coming back time and again to spend a little money here and there for your devices, or your earbuds, or your 30 dollar DVD players, or whatever. And I'm confident this trend probably stretches across many, many product types.
My advice? Spend a few extra bucks on something that has some thought put into the design, and some care into the construction. A friend of mine has went through 3 sets of earbuds in the last year for various reasons, but my $80 Sennheiser headphones have been working great for over 2 years, and sound phenomenal. My mom has spent $200 in e-cig batteries in the last year, and my $100 Puresmoker Prodigy e-cig mod has been going strong since May 2009, with $30 dollars of common rechargable batteries.