Torsion springs wear out frequently, especially here in the midwest where we deal with extreme temps. I go around and replace these springs for alot of elderly folks and charge them 50-75 bucks depending on size of door. The spring itself costs roughly 40 bucks each. There is also a gauge that is used to determine spring size you need for your door. Coil count, diameter, length of coil. All of these things determine that new coil you need. Good luck. If you happen to live in a smaller city go to your local lumberyard and they will guide you in the right direction. Otherwise look to see what type of door it is and call the company listed. Dealing with springs is a dangerous deal.
Let's dive deeper.....PublicsMoney is right. It depends on the size and weight of your door as to what type of spring you need. With doors you have HB (Hollow back), VB (vinyl back), and SB (Steel Back) Obviously hollow back is lighter so it requires less heavy duty spring. I worked there years ago in sales for about 6 weeks. The company was full of crooks. We would charge $600 to install a $40 spring. Your garage door crashed? That's gonna be a crash door reset charge that's $2500. Wtf. You can get a whole new door for 600-1000$ and it comes with the hardware. Tracks, rollers etc. Only other thing to buy is a opener which range from 150-600$ depending on quality. We had a technician that had a torsion spring go through his arm. I wouldn't advice you doing it yourself.
