I have a good opportunity to join a startup, my role will be to design and build a MVP, so far there are 3 people involved.

Absolutely. I would focus as much as possible at raising the least amount of money possible while still optimizing your businesses ability to execute on its strategy. Money isn't free, the cost is the equity, interest, etc.

1. Before you dive into building out marketplace software you might find it easier to quickly test your MVP using a SaaS product like https://near-me.com/. I am NOT affiliated with them. But in a previous startup explored the marketplace concept. Spend 12K for a year on a SaaS product then spending so much more doing it from the ground up. If you gain momentum then start to build out your own platform. 2. Technical Co-founder is the person who will help bring your idea to life so enough skin in the game to keep them motivated and keep him/her hungry. 3. Remember 100% of 0 is 0. So if the CTO wants 20%-25%. Does it really matter at this point? No it doesn't. 4. Make sure you understand how to tackle the marketplace problem of the chicken and egg. You have supply on one side and demand on the other. What comes first? You should think through that as well.

You are thinking about it wrong. Don't think of your organization as a pie. Think of it as a house. When you add an extension (say a new kitchen) to your house, the value of your new kitchen now accounts for a larger *percentage* of your house, more than it did before. But something else also happens. Your house is now worth a lot more. I highly recommend you watch the series on raising money for a startup by the Khan Academy - http://robt.co/1u1wCsx

The first question cannot be answered as asked. The starting point is agreement on how the investors are to get their money back. Neither you nor your attorney should attempt to value the business. Who you turn to depends on the business itself. There are norms available even for pre-revenue firms but usually not term sheets for specific transactions.

It's good that you know what you want, but I expect that here you will be constrained by the market. I've been involved in startups a long time, and I have honestly never of a developer who is not only being asked to work for no salary, but to buy in with cash. You may see it as "giving away equity for nothing", but they're going to see it as payment for work. "Please pay me so I'll let you work for free on my business that, as far as you know, will probably fail" is not a particularly appealing pitch to anybody who can turn around and easily get a solid salary. Instead of buying in, the typical way this is handled, at least in Silicon Valley, is to adjust the amount of equity. The more value they bring, the more equity they get. The more valuable the company is right now, the less. The lower the salary, the higher the equity. Whatever relevant factors get rolled up into a single number. Yes, you'll definitely want vesting. Hereabouts 4 years is pretty typical. For people joining later, a 1-year cliff is typical. But if they are coming in early and aren't getting salary, then I think it's normal to start vesting right away. As to the actual amount of equity, there's really no guide for this. If you're before both investment and revenue, there's little objective data to say what the equity is worth. You can see noted venture capitalist Fred Wilson talk more about that here: http://avc.com/2010/11/employee-equity-how-much/ I haven't watched it, but he also did a live class on the topic here: http://new.livestream.com/Skillsharelive/MBAMondays/