Ooma: What do you need, besides $399!

You need the $399 :-)

You need a phone receiver.

You need a broadband internet connection. Its not exactly clear what the minimum internet speed requirements are. But going by the industry standard, a DSL 512kbps line should be good enough

Optionally a landline connection from your big old (crappy) telephone company (that still works) if you are comfortable with e911.

The installation is fairly simple.

You are good to go!