SHINESTAR Universal Propane Refill Adapter for 1 lb Tanks, Propane Adapter 1 lb to 20 lb for 16 oz Propane Fuel Cylinder, Solid Brass;

You will needn't to buy another cylinder again, you can use this adapter to refill your 1lb(16.4oz) disposable bottle.

There are instructions with this adapter.
1: Put your empty 1 lb cylinders in a freezer for a couple of hours.
2: Attach the coupler to your propane tank (5-40 lb tank).
3: Attach your 1 lb tank (fresh from the freezer) to the adapter.
4: Pick up your large tank and turn it upside down and rest it securely on the corner of your picnic table.
5: Open the propane valve and shut it off when the flow of liquid propane stops.
6: Turn everything right side up and remove the 1 lb cylinder.
7: Repeat as necessary.

Pay attention to :
1:You need to turn your bulk tank upside down so liquid flows out of it.
2:You need to chill your empty tanks so that there is a lower vapor pressure in the empty tank than the bulk tank.
3:Your refilled tanks will not be totally full, but this is good because over filling can cause them to vent gas if left in a hot place.