Regarding the touch, I got one for Christmas and yes, the App store for itunes is quite impressive. I've got over 50 apps on my touch. Aside from a few of them, most everything else was free. Even if it was just a handful, I would love to see similar apps for the instinct.
Unfortunately, I just don't see anywhere near the development taking place for the instinct. And if apps do become available, I don't see them going for free.
Not from Sprint at this time, no.
We're focusing on providing an open platform for community based development - a great example is http://instinct-software.com/
There's a great opportunity for a developer to make a handset-based interface to an online application store.