Scribus for Mac is a free DTP app, which gives you a useful variety of tools with which you can complete all manner of various projects.
It comes packed with preloaded templates or you can create your own document from scratch. The template options you are presented with are professional looking and can be utilized well. Whether you're creating brochures, business cards, newsletters, PDF presentations or posters, you have several different styles to choose from.
The interface is easy to get to grips with; simply choose a template and start working. All the main tools that you will need are efficiently arranged across the top of the doc window. There are some measurement markings on all sides of the window that enable you to check your formatting and alignment with a quick glance.
The app also comes with a lot of support options to help you get the best results from your work. There is an enthusiastic and friendly community around Scribus for Mac that assists beginner and pro alike, via the mailing list, IRC channel, wiki, contracted support, and the bug-tracker.
Overall, Scribus for Mac gives you a fluid and efficient way to create all kinds of documents. It is pretty powerful for a free, open source DTP app, with some professional features, such as CMYK color, spot color, separations, ICC color and robust commercial grade PDF.