I used Sugru, which you can buy on Amazon or Target and made my own gasket. The object is to not make it so thick just about a string of 1/4 inch Surgru around the inside, screw the bottle in just enough to make a slight screw impression and then take the bottle out and let it dry for 8-10 hours.
You've now made your own gasket with a rubber material that will last a couple of years.