I'm pretty sure the thing costs more than 99 Cent to make. Of course it's expensive, but everything from Apple is expensive. I paid 50 € for my Sony Stylus for the Vaio Tap 11. It's not exactly just a piece of plastic like the ones for the Nintendo DS. They need power and everything. And my Sony Stylus doesn't have a built-in battery, you need AAAA batteries for it (I didn't even know those exist before!), so that's a factor why that Apple thing is a little more expensive. I'm also pretty sure it is of higher quality.
Long story short: The stylus is expensive, but it's not as bad as some want it to be.
Official member of VGC's Nintendo family, approved by the one and only RolStoppable. I feel honored.