h_cap
im pretty sure buzz had his own commercial that andy probably saw & asked for one. or thought it was really cool & his mom picked up on it. buzz was the cool new "it" toy, and for young boys you can never go wrong with that!!

Roger Skreet
Megalow Mart

revenge_is_silly
As shown later in the movie, there is a commercial for the Buzz Lightyear. He could have seen this while watching TV and said, "Mom, this Buzz toy looks amazing!" He could have also found it at the Al's Toy Barn and wasn't allowed to get it at the time, but later recieved it as a birthday present. Hope this helps!