The lastest version of xpadder charges at $9.99 on it's official site. If you you guys don't have windows 8 system, the version 5.3 will work fine on your machine. Here I found some places that you can get it:
Download Xpadder 5.3 (Last Freeware Version) for Windows 8/7/Vista/XP
Xpadder - Download
Download Xpadder (Last freeware version) For Free - MajorGeeks