I want to know if it will go down any further in the future it was oringinally 750. Will all these pack exclusive characters start at 750 after the first month then go down to 500 permanently or wil they go down even lower?
The "normal" progression for new heroes is going to be 1 month pack exclusive > 1 month 750ES >500ES. That's confirmed by the devs as the current model for new hero releases going forward.
Its always possible they could drop certain characters' prices further based on whatever metrics they used to shuffle the prices a few months back. But since that's only happened once and it seemed kind of random, I wouldn't really count on that. Once they hit 500 you're probably looking at the lowest price you're going to get for some time if not period.