Can you build a used car valuation product from Autotrader (or any other online classifieds) data?

I like to separate your question into 2 sub-questions: #1 How do we determine which side to charge? #2 How much is the right amount to charge? On #1, my answer is that you can charge the side(s) for whom you add the most value. In your examples, Uber really solves a big problem for drivers, it's that they sit idle for a good part of the day, so are willing to pay a lot for new leads. (their alternative is no work) Consumers are charged more for the convenience of a private car but they are probably not so much willing to pay more for a taxi, even if they can hail one from their phones. For AirBnB, it's a mix, it's a way for landlords to monetize idle capacity which they are willing to pay for, but it's also a way for a renter to pay less than they would normally pay for a hotel. On #2 (how much), I like to triangulate a number of factors: - What's the maximum amount I can charge one side, while still being a good deal for them. - How much do I need to charge so that I can become profitable? (the economics are quite different if you charge 3% vs. 12%) - What are comparable services charging for substitutes/competitive offerings? I will just add that there is no formulaic way to determine pricing strategies (curated vs. open), and it's a lot more about what's the comparable and what the value delivered is. That's how I approached the question while deciding the business model at ProBueno.com (my startup)

Check out https://www.balancedpayments.com/ They are made for marketplaces. Airbnb CEO among others invested in them and they have some of the best pricing/payout fees. Also some good info on http://www.collaborativeconsumption.com/2013/10/08/online-marketplaces-are-hard/ One of Balanced Payments co-founders is writing this blog series on marketplaces.

I'm the CTO of https://3dagogo.com a marketplace of proven to print 3D designs. We look at the two sides differently. There's not a single customer. In our case you have designers and purchasers ( sometimes the same person can be both ). Cost and methods for acquiring designers are very different than those to attract purchasers. I would clearly separate the sides and come up with separate cost structures. In my opinion when you're looking at the marketplace from the purchaser perspective, the other side's acquisition costs can be seen as fixed marketing costs.

I always suggest going "uncomfortably narrow" initially so that you can really dial in the user experience and build liquidity first. Going broad will be tougher as there's too much noise to signal. Also, it's best to fake the supply side initially of you can to improve the buyers side first, then figure out supply & quality afterwards if customers are buying and you've proven out a demand strategy that will work.

Your support software should cater to your needs, depending on how your business operates. Fiver uses Vanilla forum and Zendesk. Thumbtack uses Zendesk. Not sure about AirBNB, their help center seems to be custom. Depending on how well funded your are, I would recommend starting with a free plan with one of the help desk SaaS products, or even using open source ticketing platform. Then, as your needs grow and you need integration with your marketplace, there's no reason you can't scale and migrate.