I made this chart to help me see card prices and stats.
It is from today, Feb 16(2023) it has just gone midnight here so it may show as posted 17 Feb but prices are from 16th. Of course prices can change, this is just a snapshot although some patterns remain. I remember epics being the cheapest power for a while. The chart should be pretty self explanatory. It is only for Chaos and newer reward cards(which share same power/rarity.) These are the cheapest ones so it made sense. Also shows max cost(max lv) at current prices. It seems staking cards on Towers and Land will come so I am guessing power and rarity may be significant there. I will make more charts in future. As always, not financial advice. Let me know any feedback or improvements.