Continuity mistake: When the "Toothfairy" met the cat for the first time after they fall out of the bed, you see only a piece of block, and 2 shots later there is a skateboard next to it . (00:35:45)
Continuity mistake: When the Rock enters the first kid's room, pay attention to the blue building block on the floor and how it is turned. Just for the shots where the cat arrives and The Rock has to hide behind it, the block rotated 90°. It goes back to how it was a moment later, otherwise the curved path would not face the door and the Rock couldn't fly towards the door. (00:33:30 - 00:36:15)
Continuity mistake: Right as The Rock lands in the Tooth Fairy world for the first time in his dazzling tutu, one of the first fairies that cross his path is a black fairy, moving from what would be The Rock's right to his left. In the next shot he's all the way to the Rock's right. In general in the scene there's a lot of extra recycling, a Hispanic fairy with heavy makeup and big cheekbones, quite recognizable, that keeps advancing behind The Rock without ever really moving. (00:11:55)
Continuity mistake: The Rock is goofing around with his fiancee's little girl playing a vampire. Randy scoffs and goes to open the fridge. In the first shot he's reaching for both doors, in the closer shot he is opening just one, brief cutaway shot and then he's re-opening the same door. (00:05:35)
Continuity mistake: Derek invites everyone to dinner after the makeover party but he receives a call on his blackberry. He handles it with his right hand, but in the last shot he's holding it with his left. (00:49:15)
Continuity mistake: As he is walking with Tracy, The Rock meets a random fairy questioning his attire. The guy has a single string showing above his left shoulder, doubling in the next shot. (00:12:40)
Continuity mistake: When a pint-sized Rock argues with Tracy on the doorstep of the first kid, the shadows of the two change depending on the angle of the shots. (00:32:00)
Continuity mistake: When the Rock is giving the kid his present (a hockey stick) the paper covering it changes height in the shots. He even takes the paper almost all the way off when in the next shot it is back on.
Answer: It was all Black Market merchandise. Usually not of any good use; total rip-off.