Just run it from the hose! If it's good enough for human consumption its good enough for goldfish. You would do well to buy a giant-size jug of dechlorinator for initial fill up, and for times when you drain more than 20% or the pond and refill. For topping off, I use no dechlor at all. The waterfall and stream, with all the splashing, dissipates the chlorine pretty quickly.
I pay my water bill 4x per year, I think it's about 10 bucks more per payment. not too bad. I think the pump costs about ten bucks a month in electricity also. None of these costs will break the bank for me.
The worst was 2 years ago, we had a drought and were under water restrictions. I wasn't supposed to use the hose at all, but I did break the rules about 4 times that summer only when the water level was severly low. be danged if I was gonna let my fish die. Pretty funny running the hose at 1am in the pitch darkness as to not get caught!