do you carry plastic gears 1 half inches in diameter

They carry a wide range of stuff. You're far better off calling the store directly and asking the question. They probably don't check the Google forums all that frequently for specific questions, plus the store employees are able to go to the shelf and check.

Their stock rotates all the time. Last time I was in there they had a bin with assorted gears in there

Call the store directly, i was there about a year ago.

I know that they carry gears, along with all sorts of other mechanical goodies, but I can't really say what sizes. I normally go in to look around for what I need, but you may want to call them.