I've had this thing for nearly a decade and I have only put it in my GBA once (to make sure it works). I originally bought it because I thought it was neat. It was originally sold for $11.99, I'm going to ask $15 for it. There were only 500 of them made.
The website, for your own research: http://2004mbit.gbadev.org/
SOLD for $15 to CoinCollector.
E-Mail me at [url=mailto:alec2dabreen@gmail.com]alec2dabreen@gmail.com[/url] for the quickest response.