What ranking factors are used for international search?

Are there any online car buying sites that search both new and used cars at the same time?

• I'm in the market to buy a car. Honestly I don't really care if we buy a new or a used car - I'd probably prefer to buy a slightly used car (such as a dealer's demo model) and avoid a big chunk of a depreciation when we drive off the lot. But I'd like to do a lot of research first, see all of my options and make an informed, rational decision. This means I'd prefer to be able to search for both new and used cars via one search. I'm only interested in options for  the US for myself - but if there are great non-US options for others  feel free to leave those as well. Other features I'm looking for: - ability to search via features that matter to me (I don't know how to use a manual plus I live in hilly SF - I only want to look at automatic transmissions). Mileage is also a big factor, as is overall emissions. But so to are less easily searchable features such as interior layout, visibility, blindspots, comfort (I've been literally in pain driving older models of Prius, I hate the center console design of some cars such as the Mini and the Prius etc) - ability to compare what dealer's are offering with neutral 3rd party guides (for example Edmunds online has estimates of what people are actually paying for various models) - present, ideally, financial options such as Lease vs Finance vs Pay Cash so I can run the numbers (including trading in our existing 10+ yr old car)

• Answer:

  There aren't too many options for new and used vehicle searches short of sites like http://Cars.com, http://AutoTrader.com, and Craigslist, but those are not anonymous and will ultimately still require you to have to go through a nasty search and negotiation phase once you've found something to buy. This is why I built (http://bidzuku.com). We've designed Bidzuku to keep your search 100% anonymous, remove all negotiation, and deliver the best deals. Our goal is to help buyers get exactly what they want for exactly what they want to pay while feeling confident that the vehicle the dealer is offering is actually on their lot. Bidzuku allows you to pick your car, new or used (because we know not everyone can afford new car smell), its features, and your desired monthly payment. After that, your anonymous application is sent to dealerships in your area and they have an opportunity to compete for your business by placing bids. Bids are all assigned a relevance value and then delivered to you, the better the match = the higher the value. Finally, you may pick the bids that suit you best, print a certificate outlining the details of the offer, and set out to make your purchase! While we are launched, we are not yet available in your area. I want to be clear on something though, no online tool will be a better negotiator than yourself. If you do your research and find what you want, know what you can afford, pick up the phone and state your demands. Don't settle for anything less and remember that your most powerful negotiation tool is your ability to walk away from a deal that you don't feel suits your needs. This is likely the second biggest purchase you'll ever make, don't get caught up in the price and lose sight of getting what you want - your dream car. For those that still don't feel comfortable doing this, there are sites like mine that can help. Hope this helps you see a bigger picture, and good luck with your purchase! Edit: I'd also like to add that as far as side-by-side, research based comparison goes, for new cars only, http://TrueCar.com is probably your best option.