This is not, repeat not an ad for any particular auto parts website. This is a condemnation of Kragen, Napa, and other such auto parts stores. Especially Napa because I extra-special hate them, but really, they all have to pay.
I understand that there is a major difference between running a retailer and an etailer. An auto parts store takes up a certain non-negligible amount of real estate and has to hold a certain amount of stock. Of course, I'm usually driving slightly odd cars; anything from Subaru was sold in much smaller numbers than anything from Toyota, for example, and so parts are more expensive. But they don't have to be THIS much more expensive. Here's an example, comparing prices on my '93 Impreza LS's throttle position sensor :
| Site | Brand | Price |
|---|---|---|
| partsamerica.com (CSK) | Niehoff | $290.99 |
| partsamerica.com (CSK) | Standard | $287.99 |
| partsamerica.com (CSK) | BWD | $292.99 |
| napaonline.com | CRB | $284.00 |
| carpartswholesale.com | Delphi | $62.95 |
| partstrain.com | Delphi | $62.95 |
| thepartsbin.com | Delphi | $48.85 |
Now, you're surely saying "but those are different brands!" Yes, yes they are. However, a TPS is a very simple piece of equipment. It typically contains nothing more than a potentiometer. The remainder of the sensor is some plastic, including some sort of connector to go on the end of the shaft in the throttle body to which the butterfly valve attaches. There's also a plug on there someplace so you can connect it to the computer. This is not a $300 part, period. Anyone who would sell you such a part for three hundred bucks is actively harming the auto parts market.
This is simply an incitement to always check on-line before you buy auto parts. It's not always cheaper! But you can often find a MUCH better deal just by shopping around a little. And this is not the kind of part you buy used, either.
A final note on Napa parts: Never buy a Napa remanufactured part. I am deadly earnest about this. Buying a rebuild kit at Napa and rebuilding something yourself is fine, because Napa doesn't sell the stuff they use to refresh the seals in brake master cylinders or carburetors or what have you. But if they bring out a remanufactured part and it's in a Napa box, tell them you don't want it immediately. It will not last. Napa has a complete inability to perform any kind of rebuild (or rather, whoever they outsource it to can't manage it) and unless you're just trying to get a car "fixed" and sold off to some unsuspecting dupe, in which case you are an asshole and I hope you get hit by a bus or a train, their used parts will not help you. They have an amazingly crap website, too.