When did you sign up for advantage? If you signed up to start for the 2017 tax season, you will still have to pay for the 2016 program, which is the only one currently available.
If you signed up for the 2016 season (before last November) then you should have the downloadable installers in your account. If you are being asked to pay again, you are probably logged into the wrong account.
Advantage does not offer a discount on the downloadable installers. It is still cheaper to get them from Amazon, Staples, or Best Buy. But Advantage gives you both Mac AND PC downloads, which may be useful if you use both types of computers. Advantage also gives you the download and a physical CD, which some people like. And Advantage gives you the earliest access to the program, and access to a priority customer support telephone number.
