SoundCloud has one limitation to that. If you tend to share a lot of tracks (let's say so to recordings) you will have to be aware of the time they lenght. It's not limited ot particular track how long it is but the lenght of the all recordings you upload. It works like this:. (I don't know how much time you have with free acount though) If (let's say) free acount allows you to upload about 3 hrs of lenght you'll have with that limits. Now you have to decide will you upload one track in lenght of 3 hours or you'll save that time for many more tracks (what I know you'll do of course).You can upload more than just 3 hours of files of course but that means that those old will be hidden and new will come on or you'd be prompted to delete old files according to upload the new ones. (I'm not sure which option is correct because I actually use Pro acount on SoundCloud and it's without any limitation of amoun tof uploaded time).
YouTube (as you know) has it all for free. However (as much as I know) you'd still have to convert audio files into any video format in order to upload it. It is fine with this forum to use either YouTube or SoundCloud because with posting the link the forum software recognizes the services and embeds the video or audio by itself.
Audacity is free and good enough to compose audio files together while you can also record directly to SoundCloud if you allow to it the access to your microphone. For really short recordings I many times use that option (however you can't edit files that way of course).
For making videos I use whatever camera being it webcam, phone, photo camera or something else but I compose them with MAGIX Vegas although I don't know where and when I've got it because it's not for free. (I speak of me speaking of course). All the rest I animate with all kinds of software which I won't name all here (except it's of someone's interest).