ESTA has an application fee of $4, and if approved, an additional fee of $17 is charged, for a total of $21.
ˈɛstə hɐz ɐn ˌæplɪkˈeɪʃən fˈiː ʌv dˈɑːlɚ fˈoːɹ, ænd ɪf ɐpɹˈuːvd, ɐn ɐdˈɪʃənəl fˈiː ʌv dˈɑːlɚ sˈɛvəntˌiːn ɪz tʃˈɑːɹdʒd, fɚɹə tˈoʊɾəl ʌv dˈɑːlɚ twˈɛnti wˈʌn.