If you want to get free gift cards you have to do some work to get the free gift cards so in reality they're not really free.
But there are many legit ways and websites to get free gift cards from and all you need to do is take some simple surveys, watch videos, browse websites etc.
And then when you get enough points from doing those surveys, watching videos, viewing websites etc then you can redeem those points for cash or gift cards.
One website that you can get free gift cards from is
https://grabpoints.com/rewards/free-google-play-gift-codes/
But if you look online there are many others as well.
Here's another website to get free gift cards.
https://ebonus.gg/prizes/others/google-play-gift-card