Selling Manager Pro is free to store holders but will cost $9.95 per month if you are a non-store holder.

The basic Selling Manager (non pro version) is also available free to non-store holders. We use it on our non-store IDs.

You just don't get all the inventory control stuff and some of the reporting and download options but otherwise it's the same.

But you do need to subscribe to get it tho.