Dragonframe offers a legitimate trial version. While it watermarks your images, it allows you to learn the full interface and test your camera compatibility.
Programs like cloudstopmotion or qStopMotion provide basic frame-grabbing tools for free without the security risks of pirated software. Dragonframe v4.0.2 Free Download
Tools to import dialogue and map out mouth shapes (phonemes) for characters. Dragonframe offers a legitimate trial version
The 4.0 release marked a significant jump in the software's capabilities: Dragonframe v4.0.2 Free Download