Are you still looking for a good dictionary for the Polish language class?
If so, go for the KF American English <> Polish dictionary. Only from September 3 till September 9, the price is just $8.99 ($12.99).
Based on the American variety of English, the KF American English <-> Polish Dictionary features over 690,000 headwords, idioms, phrases and translations and includes a simplified guide to grammar and pronunciation in both languages.
Available for iOS