According to the Small Office product page, which hosts a savings calculator; you save $650.04 in the first year if you pay your old phone company 80.00 per-month for 3 lines. Here’s the link:

Right above the calculator, that page says:

Unlimited calling in the U.S. and Canada starts at only $19.99 a month per line.

That’s $60.00 per month for the three lines of Ooma service, a savings of $20.00 per-month (before taxes). The monthly savings total $240.00 per-year. That’s before deducting the $250.00 cost of the base system.

My question: Where do the numbers the calculator gives come from?

Yes, you’re correct the savings calculator is using a wrong formula. Given the current default values, you’d actually only start have a positive savings the 2nd year because the first year’s savings would cover the cost of the hardware. I’ll ask our web team to correct it.