It's only free as in free beer if it's free as in GPL, otherwise you have to pay for a commercial license. GPL means you have to provide source if you distribute the app. And isn't there also an incompatibility with Apple's App Store terms and the GPL (VLC case)?
[Sencha] Ext JS commercial license is $329 per dev. The $600 includes optional tech support. There's also a $995 that includes the Designer UI builder, Sencha Touch support & Sencha Touch Charts.