The simplest garage door part to replace is the remote. Whether you would like a smaller remote control to replace an old clunky one or give a supplementary one to kids or guests, the only thing to do is search for replacements made by your door manufacturer. Replacement garage door remotes usually cost between $15 and $35.

When kids or pets are part of the household, many homeowners like to have a safety beam - an invisible beam that will cause the door to freeze if it detects anything in the doorway. This saves squished toys at the very least. If your door opener is equipped to hook up to a beam, this is a simple garage door part for any homeowner to add or replace. Generally, beams do not have to be made by the same manufacturer as the garage door machinery. Expect to pay less than $40 for a whole set.

Shopping Around

Because garage door parts are so specialized, it is unusual to be able to go to a local home store and just pick up parts. Before the internet, the best bet was shopping in a professionals' catalog, but buying just one part might not have been possible. But the internet has revolutionized shopping for everything, including door parts.

Internet retailers and auction sites offer probably every door part anyone could need, in a way that makes it easy to search and compare prices. An internet search will bring up many retailers and auctioneers.

When shopping for door parts online, use the same good judgment you would buying anything else. Before ordering from a site, check out shipping costs, applicable taxes, and return policies. Look for retailers that have high ratings on independent sites like epinions.com or yahoo shopping. Ask and make sure that the parts you order are brand new with a warranty, not refurbished.

More advanced DIY enthusiasts can fix most parts of a door opener: gears, carriages and circuit boards. However, hiring a licensed, bonded professional is a perfectly good idea too. Working with electricity and machinery can be dangerous, or at least problematic, so plenty of people bring in a professional to do garage door work.