So I have seen this on other servers and basically there are vote crates (You get a vote key from voting instead of 6k and you can win prizes in it)
Then we could have donator crates where once a week the donor can do /kit (their rank) and they get that key. E.g. I'm ult and I do /kit ultimate I get an ultimate key and open the ultimate crate. I could win money, rare materials etc
Obviously the rarer and more valuable it is, the lower the odds of getting it are.