If they wrap up the cloud storage they use for pokemon on it and make a stable service, I would be willing to $30-to-$40/ year for what they currently are saying about it.

If Nintendo were wise, they would have free basics like online play with things people could purchase as add-ons such as DLC.

Given how little Nintendo is offering with this, it best be not much more than $4. I don't really mind paying for online: it's been industry standard in the best console services for years. But it's also industry standard to offer free games that, at a bare minimum, you can keep for as long as you are a subscriber. Monthly rentals of one ancient game a month ain't really the same, but it evens out if the price is cheaper and the online service is still good.

Free, or payable with those useless My Nintendo platinum points :P

I expect the online to revolve around My Nintendo as was previously stated

If it ain't free I don't care because I won't ever look at it anyway.