The ultimate radio device was the Mattel Radica Girltech IM ME, a $12 pink toy pager that some hacker bought as a filler item on Amazon
https://web.archive.org/web/20111204042145/http://www.hunterdavis.com/archives/333
It's been used as a spectrum analyzer, a jammer for police radio communications, a sesame to open garage doors... Mattel doesn't produce them anymore and they go for insane prices on ebay today.
http://samy.pl/opensesame/
http://travisgoodspeed.blogspot.com/search/label/imme