Tips for becoming a Game Designer?

I already have a Bachelor’s degree in another field and I would hate to spend $20k on a game design degree that is essentially worthless in terms of “getting” a job at a game design studio. I know most companies want someone with experience but as we all know, gaining that experience is always the tricky thing. Besides designing an independent project on my own, would anyone recommend volunteering to work for free in my spare time? Otherwise, any other tips that might help would be appreciated.