1. Do Your Research
There are two websites every parts shopper should visit before buying. The first, Car-Part.com, offers the largest database of used auto parts in the world. The second is eBay—perhaps you’ve heard of it—which happens to be a new and remanufactured auto parts sales juggernaut.

There are a few steps to any successful search. Once you find what you need on Car-Part.com, select ‘Distance’ and then click ‘Search’ to see what its market price is in your area. Once you made note of that, go to eBay. Do the same search, and sort by ‘Pricing + Shipping lowest’. Pay special attention to the estimated delivery time in the listing. Parts from overseas can sometimes take over a month to get to your home

2. Verify, Verify, Verify!
Call the dealership to confirm your specific part number before you complete any purchase. If you don’t confirm the part number, any grief that ensues is of your own making.

You’ll learn that some parts are unique to certain engine and transmission combinations. And the list of potentially affected parts is long, from computers, modules, and sensors, to more basic items like alternators and starters.

3. Haggle, But Be Polite
It’s common courtesy for most junkyards to match a lower price for a part at another retailer in the same geographical region. There are two important caveats to this, however.

First, you have to compare apples with apples. Don’t expect a junkyard to price-match their 20,000-mile engine with one nearby that has 200,000 miles on it.

Second, when you haggle, make sure you say you did your homework on Car-Part.com, and be honest with the guy on the other line. He has the same information as you do, and if you jerk him around, he’ll know and he may return the favor, so to speak.

4. Craigslist is a Crapshoot
Craigslist isn’t always a good source. In the real world of buying parts, it can frequently become a big time-suck compared with going to a junkyard or buying online. Plus, most of what you buy on Craigslist will be sold as is, while the other two sources allow you to either exchange the part or get your money back. For this reason, I get fewer than two percent of my parts from Craigslist.