I have bought some cards in moon karts to be able to play well and to be able to get more rewards and this was amazing as I able to get more than 5k colony in this game and I was able to learn some skills as the more skills you have in the track the more ability to grab a better place in the game.
I have bought these cards as I have noticed that one kart and one driver is not enough to have the ability to pass your opponent and to get enough speed in the track and the more cards you have the more powerful you kart would be.
I have Grip Ease and Sure Turn and these ones are so good in the race and for card stats as they increase stats of the kart to be able to have good abilities with your kart in the track and to get the first position.
I have also Silent Stream as Exhaust and this one is also good in the track as it has to increase kart stats and also I have body reinforcement which I have used to generate more fuel.
My Kart is Astrokart which by the way the cheapest kart that you could find in the track and also I have Aurora which is a good driver and are so flexible in the track to pass curves and also turns.