I am looking for a program to make mockup screenshots with. I first found out I could do it with Visual Basic (uglier names I have yet to hear a programming language being called) from joelonsoftware.com. I don’t want to start learning VB now, especially since I am still in the process of learning Java. I then found mockupscreens.com, with the searchstring ‘how to make mockup screenshots’. But seeing as I am going to use this program quite infrequently, I don’t think paying $80 for it is worth it.
The mockups I’d like to do would be mainly for Windows XP (perhaps also for GNOME, KDE and Mac OSX, but these are not top-priority).
Edit: Balsamiq is suggested, but this is also a non-free program.
Balsamiq