I wanted to get a spare; checking online told me that the Apple Store wanted US$29 for the little plug, which just seemed like too much for too little, so I went shopping.
On eBay I found a bunch of auctions based in Hong Kong selling what looked like the exact same thing for anywhere from under around $2-4, and they often included the USB cable to boot.
I ordered four from a vendor and after a few weeks received them. They looked perfect, right down to the little green dot -- but none of them worked. They might start charging, but after a few minutes the iPhone would beep a few times and I would be informed that "this accessory is not compatible." And so it went for all four pieces. After sending some pictures back and forth and reading a few emails containing a combination of surprise and amazement from the vendor, my money was refunded.
Undaunted, or maybe just dumb, I went back to eBay and found another vendor that claimed to be selling, "100% Brand New Original OEM Charger and Original OEM USB Cable for iPhone/iPod" for around US$4. I just checked eBay and found this same vendor raising the price to US$10 in one auction and lowering it to $US.01 in another.
I bought another bunch and after the usual few weeks, I found that they were not OEM by any stretch of the imagination. The cable didn't fit smoothly and had plastic flashing on it while the plug, although looking perfect once again, didn't work in exactly the same manner.
Upon contacting the seller, I got my refund just about immediately. Now I'm not saying that all of the product coming from Hong Kong is bad, but my record is two for two. Perhaps this is par for the course when knockoffs seem to be a healthy business in some places.
The moral of the story is: don't believe everything you read, and if you do, use PayPal so you have some recourse in case you come across a recalcitrant vendor, which I didn't.
But the search goes on. I found something similar at Amazon.com for US$1.89 + US$2.98 shipping, and I'm waiting for some to come in.
Crazy can be defined as doing the same thing multiple times and expecting a different outcome, so I'm not ruling out the fact that I may be crazy. But It's also crazy for Apple to sell the plug for US$29... that, and curiosity got the better of me.
When these come in I'll let you know if they work and if we can all save a bundle. If they don't you can send the padded wagon and straitjacket.