It really depends on how you intend to use those lists. If your target is businesses in a certain town, then yes, use all the free resources you can. If you need to tighten up your criteria to (for example) Businesses with at least 6 employees, B rated credit or higher, and operate solely out of that location (no businesses with a headquarters elsewhere), you may benefit greatly from some paid list services. It can be the difference between dragging a net and seeing what you caught, and talking with pre-qualified candidates who you know are likely to need and afford your product or service.
I used to work for a company that did commercial and residential roofing and gutters. When I started, they were using free lists. They were doing around $25K monthly. Not bad at all, right? I convinced them to try out salesgenie from infousa. Within 3 months of using their service to search for lists of businesses and residents in the area with a certain property value and credit, we were able to increase our monthly sales to $80k. So even if you're successful with free lists, you may be missing out.