Public relations should be cost effective over the long term, although there may be less of an overall short term benefit in many areas. If, for example, you provide community services or speak at community events it is less likely that you will be marketing to a specific target audience than speaking at a business meeting or at a professional organization.
Technology such as databases, spreadsheets, graphs, PowerPoint presentations, charts and slideshows are all great additions to public speaking events and activities. Spend time to ensure these added features are professionally done and well organized to give your presentation a polished appearance.