Question about program used for youtube clips

I was looking for the best program to create a youtube video. I want pictures that come in and out and allow me to voice over as they do. I have limited knowledge of creating this.

There is a guy on youtube named "brother jake". He's hilarious and makes truth about Mormonism clips. His clips are a perfect example of what I am looking to do.

Freeware would be ideal but I dont mind buying a program. I would steer away from monthly subscription based programs such as Adobe.

Any help would be appreciated!