I have a pre-paid Virgin Mobile cell phone that my son uses. The way it works is that you must “top up” (add money) at least every 90 days — otherwise, you’ll lose the service. The minimum amount that you can add to extend service is $20. With tax, this comes out to a little more than $87 per year. But I found out recently that if you sign up for “auto top-up”, you can add as little as $15 every 90 days. With tax, that comes to just under $66 per year — saving about $21 per year. It’s like getting 90 days free. This is my kind of deal: same service, same company, just less money.