How to get power card rewards

Not everyone has a Powerup Rewards card, not everyone even sees it worth getting. Gamestop and not everyone even uses their power-up rewards card to hold store credit. People have WAY many more credit cards than they do powerup reward cards.

I finished the first punch card but don't know how to get the reward.

So then how do I get a gift card with my microsoft rewards points?

No, this is how the game should work. Putting daubers on the power card costs coins. Before you choose the numbers next time, look at where the selected numbers usually go. You will find coin numbers there- that's how many coins it costs to select 1,2, or
3 numbers on your power card. Also, these coins for power cards increase with new locations.

The prizes are awarded once the community timer runs out. This also gives you additional prizes if the community has filled the green bar. The more power bingos you get, the more your key reward will be.

Hope this helps and let me know if you have any further questions!

Have you checked under the "Social" tile? This is where I found mine. The "Social" tile is where you can gift keys and power-ups, and seems to be where the power card rewards get sent.