If you mean gold-colored glue, you can find it in craft stores (usually called "glitter glue"). If you mean the tacky "size" that is used to adhere gold leaf to a surface, you can also find that in craft or wood crafting stores.
You should be able to find it at a craft store, such as Michael's. If you don't have a store like that close by, you could also try looking in an office supply store like Staples or Office Max to see if you can get gold glue in those places.