It's a catch 22, most people want FREE Estimates. But then that can be a big waste of your time for people who are going to get ten estimates and just pick the lowest one. We give free estimates and it mostly has worked for us but definitely time consuming.
I certainly think the goal ultimately for a well tuned business charges for estimates. This takes time because you have to get enough exposure for your brand and your company to turn away business prospects if they aren't willing to pay. But...word to the wise-Any homeowner who legitimately wants to hire a contractor won't have a problem with paying up front for estimate for a high quality contractor who is knowledgeable in his field.