Magix Fastcut might do the trick. It is free:
http://www.magix.com/us/fastcut/tutorials/#c633669 My 11 year old started with that filming him, his brother, and friends doing nerf gun wars dumb stuff on their bikes etc. He would add a title and music in the background.
I juts upgraded to Magix Movie Edit Pro Premium. They give an educational discount if you have an email address that ends in .edu You can purchase software with academic pricing from B&H Photo
Magix Video Easy software is $25 academic price. It a good basic editing package. You can add in soundtracks or use a microphone to narrate and do voice-overs.
https://www.bhphotovideo.com/c/product/1309545-REG/magix_entertainment_anr004996edu_video_easy_academic.html Magix is the company that bought out the Sony Vegas software.
I think you can get a 30 day trial on most of their paid for software.