Not a lot. I used to have -$173 balance, and they rang me every week for around 30 weeks. Then they gave up, and after about 5 weeks I paid them off. I'd recommend that you pay them as they can actually get you into a lot of shit, it's not worth it over $100.
I'm assuming you supplied false information and didn't use a VPN? Although you're committing fraud, I doubt they'll be able to catch you. Paypal would have to:
1. Whois your IP and contact your local police department
2. File a police report and prove fraud has been committed
3. The police would have to contact your ISP
I don't think they'd do it for $100, but I wouldn't be surprised if they had a specific department who does just that.