Do read my post about the problems our district is causing,
before spending any money on apps.
But the ones that my students really, really love:
ABCmouse - free, easier to use on the iPad than on the desktop
computers, you just have to register
Number Munchers - my boys beg for this one. I also bought
Number Munchers: First Grade since it gets into even/odd.
Sentence Builder (Chen)
Endless Reader and Endless Numbers
Sight Word Ninja
Montessori Crosswords and Montessori Numbers
Earlier in the year:
Phonics Island (half of mine still use this one)
So many more....