From your notebook, I believe that the below given output of cell number 17 is ios data
['1', '281656475', 'PAC-MAN Premium', '100788224', 'USD', '3.99', '21292', '26', '4', '4.5', '6.3.5', '4+', 'Games', '38', '5', '10', '1']
['2', '281796108', 'Evernote - stay organized', '158578688', 'USD', '0', '161065', '26', '4', '3.5', '8.2.2', '4+', 'Productivity', '37', '5', '23', '1']
['3', '281940292', 'WeatherBug - Local Weather, Radar, Maps, Alerts', '100524032', 'USD', '0', '188583', '2822', '3.5', '4.5', '5.0.0', '4+', 'Weather', '37', '5', '3', '1']
Number of rows: 6183
Number of columns: 17
Looks like the price is at index 5 and the free apps have a price mentioned as ‘0’.
So
price = app[5]
if price == ‘0’:
should make a difference.