Here is a breakdown of Chest values and prize probabilities.
Note that they do not give straight cash and normally a combination of stuff that adds up to the values below.
They tailor it to what you play. So you can or may get a combination of Starcoins, Cash, tickets (mtt spin n go, sng), T$, free Sportsbets, Casino money.
In addition you can get tickets to the Saturday 5K
freerolls in red or blue chests and ticket to Saturday 10K freerolls from bronze chest and above.There is also a monthly PSPC sng ticket you can get.
I will not go out of the way to open a chest as the rewards in them is usually minimal unless you get lucky. Just open them through normal play.