They are available online, in thrift shops, at kitchen stores and in some supermarkets. If you have strawberry bushes or cook with strawberries throughout the year, the $3 purchase price will be a good value considering the time it will save. Hold the side of the berry between the index finger and thumb on your non-dominant hand. Keep the leaves tilted toward your other hand. The sides of the huller should pinch open and release easily with a small amount of pressure. Insert them into the strawberry about one-quarter of an inch (0.6 cm). Pull the huller out of the strawberry. The calyx will slide out with the huller. 
Purchase a strawberry huller. Pick up a strawberry. Hold the small metal huller between the thumb and forefinger on your dominant hand. Place the metal sides of the huller against the outer edges of the hull. They should sit at the border of where the top of the strawberry turns from red to white. Pinch either side of the huller and twist it. Discard the hull and wash the strawberries before serving.