Hi,
I develop my applications with the Wampserver -->
PHP Apache MySQL avec WampServer 2 : installation PHP MySQL Apache, it's open source/freeware. For scripting I use Notepad++ and phpDesigner (~85$)
W(indows)
A(pache)
M(ySQL)
P(HP)
Very easy to handle, low performace required...
For the GUI design you should work with images and css-style-sheets but there are some tools like EXTJS with which you can design your GUI.
Regards,
Simon