Animation Software

[DeadmanHedgehog]

This seems like the best place to post this. I'm wanting to make a sprite based series for youtube, but I'm having trouble finding a good program that I can afford. Best I have right now is animating on pivot and adding sound on movie maker but that kind of sucks. Can any of you suggest a cheap or free software that I can use? All I need is something that can make the background of a sprite blend in with the video background, dynamic backgrounds, and lets me add sounds in program so I can have them start at the right point.