If you are wanting to make some quick (and pretty good) looping chiptunes on the fly, one of the best sites I've found for this is:
www.beepbox.co
It's quick and easy to use, it's almost impossible to make a bad song, it is set to automatically loop, you can export to .wav .midi or even .json, it's FREE and of course the music is 100% yours! So you don't have to worry about giving credit. ;)
Anyway, I hope this helps, it really works great for what it's worth.