Originally shared by Kate Mitchell on WSJ: The Accelerators. Follow Kate on Twitter @kateDMitchell

The good news is that there are more tools than ever to market-test your idea. The bad news is that there are many of them and some may cost more than you can afford for your startup. Here are a few simple ideas for gauging initial market interest:

1. Google AdWords can tell you how many searches there are for terms like your offering, which can give you an idea how many people are hunting for a solution like what you plan to offer. You can type in a product idea and see how many searches occur for that term. In addition, a bunch of terms Google thinks are related will come up.

2. Put up what are called “ghost” pages — fake Web pages for products you might offer, including the price and a “buy” button, and then run a small ad campaign on paid search and/or Facebook, and see how many people click through to the page, and how many of those click on the “buy” button. For around $500, you can estimate demand and cost to acquire a customer. {EL note: Check out Kickoff Labs for creating gorgeous landing pages.}

3. See how many “Likes” for comparable products and companies there are on Facebook, and how many followers on Twitter. Put out images on Pinterest and see if they get re-pinned.

Being objective about customer interest is important before you commit more time and money to your idea. It may take a few tries before you get it right, but nothing replaces hard data.