I had to purchase our Wally but it was a piece of cake adding it to our existing account that has an H3 and a Joey 2 that are leased. This is the only way I could justify having it in our travel trailer.
All I did was connect the Wally I purchased separately to our home dish setup, using the connection the Hopper 3 was connected to, had it go through the setup and called Dish at the prompt where it said to. The lady I spoke with was more than happy to add it to our existing account. It works just fine for us.