The other day my son wanted to pimp his Xbox Live avatar. So we went online with our Xbox One and checked all the props you can get for Xbox avatars... and on page 14 of the props we found one where the avatar would be doing a parcours run. My son was thrilled since he's learning how to freerun, so this was totally up his alley.
Next step was for me to go online and change his settings so he could buy stuff from the Xbox store. I've setup his account such that he can only download free apps and games and all because my credit card is attached to his account. Xbox Live Gold is paid that way.
After changing his account such that he could buy stuff, we tried to buy his avatar a parcours animation.
This is when the trouble started, because still he wasn't able to buy the props for his avatar.
Next day I went online to look for some answers, and during a chat session with a very friendly Microsoft support engineer I learned that when you have a child account, you can only buy avatar stuff on an Xbox 360 console... luckily for us, I still do have an Xbox 360, two in fact. So we went onto the the Xbox 360 and looked for the parcours prop... no luck because it's an Xbox One only prop. Bummer.
Changing his account to an adult account wouldn't help either since they look at the age of the person holding an account. I guess that's correct with the credit card attached to an account and all.
I was told Microsoft is working on this, but till then, no luck for my son. He's now enjoying his Ilo Milo prop with his avatar.
I hope this little post is off help to you,