if you can find a core version ( hub and scout in same box), radioshack.com is the only place you can stil find them, onsale few times a year from $159-189, no monthly fee no tax for life.
if hub only (cosco or frys.com $119-159) or telco (amazon.com or ooma.com $200-$250) version, no monthly fee, $3-4 a month for taxes..
the hub is the main Voip ATA adapter, scout is a remote extension, looks like a phone recorder. Telco is the new version, they claim it is DECT6.0 phone quality..
$40 to port in your number, takes 3 weeks.