gCADPlus is software developed by two Australians - one a scientist and the other an engineer. Ten years ago due to our interest in CAD, we were asked teach landscape students in a local college to use AutoCAD to produce landscape plans. We found it difficult to help them develop CAD plans, primarily because AutoCAD is general purpose CAD software and not aligned with the landscape design and horticulture disciplines. To remedy that, as a 'fun' project, we developed gCADPlus, to target designers in landscape disciplines by developing a high quality, but affordable application.
Neither of us receives any funds from sales. Every cent earned goes to pay independent programmers to improve to the software. Using this model, we have been able to keep the cost of gCADPlus low and have not been forced to charge for upgrades or (as many developers are doing) levy an annual fee. Over the past 5 years we have delivered 30 + upgrades incorporating suggestions for improvements from our users. (see: http://www.plus.designcad.com.au/?q=node/71)