Wouldn't the cost of it roughly follow every other technological innovation? Extremely expensive and only affordable by the wealthy at first, then cost will go down over time as competition ramps up and economies of scale take effect.
As I said in a reply to a sister comment, maybe I'm just cynical and pessimistic, but this is the one thing I don't see those who have money and power allowing to ever reach those who don't; if nobody had to age, it might threaten their power too much.