iExplorer will always download as a free demo with no time limit and some transfer limitations which can be unlocked if you upgrade to the full version by purchasing iExplorer and registering it. You can view a side-by-side comparison of iExplorer 4's free vs. paid features on the page below:
Any iExplorer license you buy is a single, one-time payment for a lifetime license which includes all software updates to that major version (i.e. 4.1, 4.2...) as well as complimentary technical support for as long as you need it. You can view the license options at the links below:
Basic, Universal, and Family Pack licenses (personal use)
Enterprise Licenses for Businesses, Schools & other Organizations
For more information about the way the demo works, refer to these sections:
Music, Playlists and other iTunes media
The demo will still let you import up to 10 tracks at a time (batch transfer mode). To unlock unlimited, automatic transfer to iTunes, you can purchase a license HERE.
For text messages, voicemail, notes, contacts, calendars, etc, the demo will let you browse and view that data in the iExplorer window, and the registered version will unlock the Export buttons and let you transfer it all to a file on your computer.
Photos and Recorded Videos
The demo lets you browse and preview all of your photos and recorded videos, and to unlock the Export buttons, you can purchase a license which will transfer them to your PC or Mac in their original size and format.
Only available in the full version.
File System Access
The demo has no limit on browsing and managing files in the Media and Apps directories (and Root w/Jailbreak). You'll just get a "nag screen" between each transfer which can be removed and lifted by purchasing the full version.