It is discounted to 1500 when you hit lvl 51 and you get the free trial. As far as I know they've never put it on sale like that beyond that period, it's a one-time thing.

They probably should put it on sale occasionally for people who are already deep into a server.

If your server hasn't merged, when it eventually does there is an event that gives a pretty good rebate (in coupons) for recharging. Other than that you'd have to just look for a good recharge and/or spending rebate during an event to drop those ingots during.