iPad Apps for Teachers

Next term, which begins in the middle of October 2015 for my school, we teachers will be assigned iPads to use in the classroom. The department head for my section has asked us to provide her a list of apps we would like to have on the things and, of course, the costs for said apps. What I’m seeking here is the TM[sup]tm[/sup]'s input. If you’re an educator, please suggest some apps. Oh, please don’t duplicate a suggestion from anyone who posts before you. To make this manageable for me, could you post it in the following form?

App name:
App developer:
Cost:
Reason you like it:

Thanks a million!

I like NeuAnnotate+
By neu.pen
Costs $2.50; there’s also a free version

It lets me mark up and write comments on student papers. They can email me their papers as word docs, I use Pages to turn them into PDFs, then open in NeuAnnotate to read, edit, correct, comment, and email back. Students (university) like it because it saves them paper and ink, and they can read my comments, which I type in.