What it is:
A ballpark figure is an estimate.
How it works/Example:
Let's say John Doe is at a cocktail party and meets Jane Smith, who runs a contracting company. John mentions that he wants to have his driveway repaved but doesn't know whether that sort of work costs $100 or $10,000. He asks Jane Smith for a ballpark figure, knowing that she hasn't seen the driveway and isn't under pressure to commit to the price. She tells John that driveways generally cost $5,000 or $6,000.
A ballpark figure is not the same as a written estimate or a good faith estimate, which provides detailed costs and is meant to provide reliable disclosure to a customer.
Why it matters:
Ballpark figures help people get a sense of what things cost. In turn, they allow people to shop around, avoid surprises and get a sense for what is appropriate.