Today, Buy.com has an extremely good deal on a Uniden multi handset cordless phone systesm for $67.99
One corded base plus 5 cordless handsets.
http://www.buy.com/prod/uniden-d1688-5-cordless-phone-1-90-ghz-dect-silver-1-x-phone-line-5-x/234072438.html
I have this phone in the 3 handset model and it works well.
Expandable up to 12 handsets. Buy 2. You can use the base alone and use 10 cordless handsets with the other.