I use to be all about ordering online and saving money till I started seeing how good the fakes looked but how badly they performed.
I only order from Rock Auto and Amazon (not 3rd party amazon sellers). What a lot of people don't realize, I'm sure a lot of you guys do, is that there aren't tons of plants manufacturing all these auto parts. Many of them are actually made in the same plants. Some get relabeled and boxed, some get their brand stamped on them, some have different QC standards at the same plant etc etc. Many times on Rock Auto I've caught warehouse closeout deals on 'private label' parts. Rock Auto is big enough they buy out stocks of warehouses, especially on new / rebuilt parts for older vehicles. A while back I helped a co worker replaced a bunch of suspension parts on a car he bought for his daughter. The local parts place quoted him for a bunch of parts. I convinced him to order it all from Rock Auto / Amazon (depending on which had the better price / availability). The struts were a closeout "private label" at Rock Auto. They were in a plain white box, stamped with the high $ brand part #. I was curious, so we compared the $40 strut to the $120 strut at the local parts place. It was identical - down to the stampings, the paint job etc. Only difference? The $40 part didn't have a sticker and the box had no labeling. This happens all the time with auto parts.
In reality, a lot of people are paying LITERALLY for the name and that's it.
Motorcraft sensors - that's one thing I've always stuck to. But with the older parts, it only takes a little investigation to find that many of the older parts are made in the same plants as the aftermarket replacements etc.
YEARS ago I worked a second job for a large auto parts chain. Worked there for quite a while. Regional manager tried to get me to quit my day job and work with him. I literally read / listened to reports from the corporate office / marketing back when they first started pushing the "Lifetime" warranty on 'upselling' auto parts. Guess what? The "Lifetime" parts were almost always no different from the cheaper version. Different labeling, sometimes the plants that made these parts would paint them a different color, have stricter QC standards for testing / cleaning etc - but really no difference. The marketing guys figured out that "Lifetime" sounded great to customers - but in reality most car owners wouldn't own these cars long enough for it to matter.
Sometimes the mark ups are just ridiculous. I restored a '95 Bronco that my son drove daily for a couple of years. I went through that ENTIRE truck. I was installing new wheel bearings / races in the front hubs and couldn't get the new race to sit flush. Was about to pull my hair out, until I sat that original hub down next to the other hub I'd already finished. There was a bend / ding in the hub itself. Just enough to keep the race from sitting. So I needed a replacement. Raybestos sells one. I wanted to get it wrapped up.
The hub was $33 + shipping on Rock Auto. NAPA (The only place that could get it quickly)? $138. SAME EXACT part.