free, cheap or open source UML and Visio-like tool [closed]

Question

We're looking for free/cheap or open source UML tools. What tools have you used ? It's OK if there are 2 tools, one each for Flow charts and UML.

If a UML tool or Flow Chart tool is cheap(we're a NON-PROFIT), and no open source is good enough, we're open to look at them.

Answer 1

It's online, but I think yUML is the best free tool I've used. I've used Violet for University work but found it clunky and crash-prone.

yUml only supports class diagrams, activity diagrams and use case diagrams though. Here's an example of its output: