on the b..........
on the blink/fritz
c...............'s play
child's play
cost an a.... and a l.......
cost an arm and a leg
(to be) old h......
(to be) old hat
(to be) m................-of-the-road
(to be) middle-of-the-road
the c......... of the c........
the cream of the crop
to be) all the r.........
to be) all the rage
be in good s..........
be in good shape
(to) come in h.........
(to) come in handy
not break the b...........
not break the bank
get the h........... of something
get the hang of something
to be u...........-friendly
user-friendly
be on your/its last l.........
be on your/its last legs
(to be) out-of-d...........
(to be) out-of-date
(to) gather d............
(to) gather dust