First, if you literally mean MAGIX Music Maker Premium 4.5 that is extremely old and highly unlikely to run on any modern computer, even if you could find a copy of it! The current latest version is 29! So, can you first clarify exactly which product you are trying to buy for your grandson?
Thanks for the link, that clarifies which software you are referring to.
This is a little difficult to advise as the program would be best registered in his name and requires an email address.
In the case of my grandchildren this year, I gave them money so they can buy what they want and have the fun of going to the toy store. I would have preferred to take them to the store however the current virus situation prevents that.