If you deal with videos professionally and need to be in constant collaboration with clients and colleagues, Google Drive can’t be beaten to backup videos. Its integrated file sharing option is a breeze to use, and all you or anyone you share your files with requires is a Gmail account (and let’s be honest here, who doesn’t have a Gmail account these days?).
CrashPlan is completely free if you're just doing local backups, but even online backups are affordable, with CrashPlan+ accounts starting at $2/mo (per computer) for 10GB of online backup storage, and going up to $4/mo (per computer) for unlimited online backup storage and $9/mo for unlimited online backup storage for a whole household. You can check out their plans here, and try them free for 30 days with a new account.