Our Technology Director set up a single iTunes account for our iPad cart. This is mostly because we have only one cart at this time. Right now, I or our tech director update the iPads when needed or add apps when teachers request. If we come close to our spending limit, I assume the tech director will tell me. I do tend to look mostly for apps that are free or lower in cost, especially when trying them out for the first time. If the app proves useful, then we go for the pay for version. For elementary education, most of the app prices are very reasonable.
If we had more carts of iPads, we would probably need to rethink how we do this. Some schools give itunes card to the teachers who have classroom sets of iPads and in that case I would think the teacher in that classroom then has more control over what he or she decides to put on them.
I imagine each school is a little different in how they use iPads and therefore will have differing ways of distributing apps to them. If getting funding is a problem, perhaps teacher wish lists or requests for donations could be in the form of itunes cards. This could certainly be fruitful in gaining a library of apps.
