I've found that Dave Brown aluminum spinners seem to be pretty good value. Tower Hobbies offers a 3" Dave Brown aluminum spinner for $24.49. Dave Brown part #S230-8230. They also have the 3" Great Planes aluminum spinner for $24.99. I've found that alot of hobby shops will order the part for you, if they don't have it in stock, or don't normally stock it. This way you can save some shipping if all you need is a single part.