Today, when the Lean Startup movement is so wide spread, it became almost non-professional to build a product before first validating the business need. So how does one validate the business need without a product and with no marketing budget?
First, let’s distinguish between products and services that target medium and big enterprises, and those that target consumers and/or small business (e.g. designers and freelance developers). If your product targets medium or big enterprises, then the way to go is to make a list of customers with the highest potential to buy your product and get out of the building and talk with each one of them. For each potential customer it’s important to speak with the person that has the decision making power to buy your product.
If you’re targeting consumers and/or small businesses, then there are two main routes you can choose from. If your idea is for a tangible product (e.g. special earphones), then your best option would be to create a KickStarter
campaign (UPDATE: I forgot mentioning Indiegogo as a great alternative to KickStarter). On the other hand, If you have an idea for a service company (e.g. Dropbox), then it might be wiser to create a landing page [see note #1], and try to make people register to a mailing list that would notify them when the service is available.
Notice that in all cases, you shouldn’t publish your product or service as if it’s already available. Be honest and tell people that you’re working on the idea. Offer them to register to become a beta user when the product is ready for testing. People love being beta users and provide their feedback. You can also offer them to answer a survey about the product [see note #2]. When making a survey, always add one open question that allows participant to give you general feedback. You’d be amazed what great ideas people would give you for free.
If you either succeed in raising money for your product through KickStarter or convincing people to give you their email address, then you’re probably answering a real market need. However, if your KickStarter campaign fails or you can’t convince people to give you their email address, then it doesn’t mean that you should immediately abandon your idea. Instead, try to listen to the feedback you get from people. Sometimes, you might just need to slightly change your product or service to reach product-market fit. And sometimes, it’s just about communicating your idea in a different way or to a different segment of the market.
 There are a few good apps for creating lending pages without the need for any coding. Here are three of them:
 There are many apps that you can use to create online surveys. I usually use PollDaddy (http://polldaddy.com/