On a large scale
In large numbers, in a large size.The company likes to do everything on a large scale.
On a fool’s errand
Involved in a useless journey or task.I was on a fool's errand as I looked for a store that sold organic candy.
On a first-name basis (with someone)
Good friends with someone.I am not on a first-name basis with my neighbor.
On a dime
In a very small space, quickly.My new car has very powerful brakes and is able to stop on a dime.
On a diet
To be eating less food so that you can lose weight.I was on a diet for several months last year.
On a budget
With an amount of money that you can or want to spend for something.The man has no job and is now on a budget.
Old hat
Old-fashioned, not new or different.My job has become old hat and I am now tired of it.
An old hand at (doing something)
Experienced at doing something.My father is an old hand at building kitchen furniture.
(as) old as the hills
Very old.The building next to the library is as old as the hills.
Offbeat
Unconventional, different from the usual.The movie was very offbeat which is just the kind of movie that I like.