The electronics should be somewhat cheaper, but the Saturn V didn't have much of that to begin with. I have no Idea about materials, but engines we'd either have to take the same (they're still among the strongest ever developed) or we'd have to engineer a completely new one, as we don't have those kind of engines in stock (we don't need such monsters currently).
As Ark said, The costs for dusting off the design are probably quite considerable, not too far away from inventing it a new, especially if you want to employ newer technologies and not just replicate it.
As for the pure costs of building one, that would depend on how many you want to build. If you would want only one, the costs of setting up the whole manufacturing line would probably raise the price well beyond what it was in the sixties.
Also, the number would be a lot higher than in the sixties, because of inflation. But accounting for inflation, I'd say it's a safe estimate to claim that repeating the whole moonlanding program today wouldn't be significantly cheaper than it was back then.