Have money, time, etc. to play with
Definition 1 of 1
Pro Tip 1/3Informal Context
The phrase is informal, suitable for casual conversations but not for formal or official settings. 
Since we have time to play with before the train leaves, let's grab a coffee.
Pro Tip 2/3Positive Connotation
The phrase often implies a positive opportunity to use extra resources creatively or freely. 
Our project is ahead of schedule, so we've got some extra hours to play with for testing.
Pro Tip 3/3Not Always Literal
The phrase may not imply literal play, but rather the freedom to decide how to use something. 
With the bonus I received, I now have extra money to play with for investments.