Most Honey Bee Supply Companies sell the Queen Lures.
I use Lemon Essence Oil, it's made from Lemon Grass.
Most Health Food Stores will handle it or you can buy it online.
A small bottle of say 1/2 ounce or so will last a long time.
You use it sparingly, too much and you will actually repel the scout bees.
You can take a small pill bottle and drill a 1/16 or smaller hole in the lower side, fill it with cotton balls and just add a couple drops of the Lemon Grass Oil and seal it up.
Or take a large diameter soda straw and cut it in 2 inch lengths, stuff it with cotton and add a couple of drops of Lemon oil, then staple it in the trap.