Everything is free at
pocket pc freeware
Some of my recommendations are:
Magic Button(task manager)
GSFinder+ (file explorer)
Calc98 (good calculator)
Betaplayer(watch movies)
GSPlayer(listen to music)
Where is my RAM?
PHM Regedit(registry editor)
Bizzdev NetUse (map network shares)
And while it's not free, get Sprite Backup - soon!