Q: Why don't I have any iWork apps?

I have a MacBook Air 13-inch,Mid 20131.3 GHz Intel Core i5,4 GB 1600 MHz DDR3,128gb.

I used to have OS X Yosemite 10.10.3.

I updated it to Mac OS Sierra.

After I updated it,I couldn't find any of the iWork apps and GarageBand and i-Movie.I searched the app store but it said that I need to pay.

Please give me a solution.