Living at home is making me depressed, but I can't afford an apartment. Ideas?

I started my own web design business about a year and a half ago. I had my own place which was great—I was doing well—but I couldn't afford it after I quit my full-time job (plus all the costs of starting a new business), so I had to move home.

It's been a vicious cycle because I get depressed when I don't have a place to myself, which makes me unproductive, which prevents me from earning enough money to move out.

I'm wondering if anyone has any ideas on a low-cost place to work where there would be WIFI but no other people around.

I know that's probably unlikely... but I just thought I'd ask in case other introverts had been in this same situation.