Often I’ll find myself wanting to show someone an idea for a user interface. A few years ago a colleague introduced to me to Balsamiq and I’ve loved it ever since. Its simple to quickly visualize my ideas and its easy enough that I can sit next to someone and we start moving stuff around until we’re happy with the look. It exports to .pdf, .png and the windows clipboard so its trivial to send the idea through mail or *gasp* print-it-out.
It has plenty of UI elements included by default and you’ll be well set for anything related to web, application, tablet or phone. There’s also lots of plugins available. Some eye-catchers are integration with Confluence and JIRA. The pricing for stand-alone and for the OnCloud versions can be found on Balsamiq’s pricing page
Here’s a video showing how to integrate Balsamiq with JIRA: