Complex sentence: When she asks for the mini-Buzz Lightyear--themed toy on display, her mother is told the restaurant's supplies of them have run out, and the only one left is for display only.
Split into simpler sentences: When she asks for a mini-Buzz Lightyear--themed toy, she is told the restaurant's supplies of them have run out. When her mother asks for the one on display, she is told that the only one left is for display only.