What is the pros and cons of a marketplace website like houzz.com, zillow.com and trulia.com where users send mail to professional without logging in?

You usually only recognize the commissions as revenues and use the term "Gross Merchandise Value" (GMV) to describe the size of the marketplace (value of all transactions going through the site)

I think you're looking at this the wrong way. Your customer acquisition cost is not something you should benchmark against other businesses. Without knowing more, like your short and long-term goals, it's impossible to answer. Two companies with similar business models may have different answers to this question. A venture-backed startup trying to keep up with aggressive revenue goals may be able to stomach an astronomical CAC. A bootstrapped startup that is not seeking venture money may aim for slower growth and much lower CAC. I suggest setting up a call with a marketing or finance expert to determine what CAC is appropriate for your company and how to get there.

It depends on a number of factors but I'd boil it down to two key things to start: 1) What is your real cost to provide a free plan or trial? 2) Who exactly is your customer and what are they used to paying and who and how do they pay today? When you say "online workforce marketplace" it sounds as though you're placing virtual workers. If that's the case, or if you're paying for the supply side of the marketplace, the question is how much can you subsidize demand? Depending on where you're at in the process, I'd also question how much you can learn about the viability of your marketplace by offering a free version, assuming again, that free is actually a real cost to you. I was part of a SaaS project that started charging people for early access based mostly on just a good landing page (we clearly stated they were pre-paying) and were amazed at the response. I've also run a SaaS product that offered free trials and realized that the support costs and hand-holding and selling required to convert from free trial to paid wasn't worth it, this despite the product's significant average ARR. You might be better off providing a "more information" sign-up form (to capture more leads) and let them ask for a free trial while only showing your paid options. I've been amazed at the lead capture potential from a simple "have questions? Click here and we'll contact you" This is all the generalized advice I can offer based on the limited information I have, but happy to dive-in further if you'd like on a call.

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 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)