I agree with PP about adding the hopper when you're there. Since it's a flat rate, you can wait till you actually need to hop to buy it. You may find you can rearrange your schedule or you won't feel like hopping when you're there and you will have saved the $. However, if you buy it now you can't take it off when you're there.
Last time we bought the hoppers and used them, however next time we'll wait till we get there to buy the hopping added on.