We're not going to put a number on this page that isn't tied to your actual door, because it wouldn't be honest. Cost depends on spring size, whether it's a single or double door, whether the drums and cables need replacing along with the spring, and whether the opener itself is original 1960s-70s equipment or a later swap. What we can tell you is what drives the cost up: a door that's been forced open on a broken spring often bends the track or strips the opener gears, turning a spring job into a bigger repair. A door that's just noisy and slow is a much smaller call than one that's stopped moving entirely. If you want a real number, the honest way to get one is to have someone look at the door in person - phone quotes on garage doors are guesses, and we'd rather not guess at your expense.