I guess you missed the she couldn't find a Wii part? I assume the working and raising the kid on her own doesn't leave her a lot of time to wait at Best Boy or Toys R' Us at 7 in the morning.
Even if he didn't ask for it, the kid should be happy and grateful. If the little shit can't appreciate that his mother has to take care of him and work then I don't know what to say about him.
Whether he'll be happier or not with the 360 she did something really nice and thoughtful for him. Ask the kid if he ever heard the phrase it's not the gift that counts, it's the thought.
-edit
Just a note-- the little shit comment isn't necessarily about this kid since he is grateful, it's in general about people that don't appreciate the things people do for them.
-edit #2-
Er no, still bad at explaining myself. I mean that anyone who gets upset over somebody (themselves or someone else) not getting everything on their list even though someone did get something they obviously had to make sacrifices to get to make them happy should be thankful. They shouldn't make some long rant.
Also keep in mind the op called him a little snot too 
