There’s no such thing as a free lunch
Definition 1 of 1
Pro Tip 1/3Hidden Costs
The phrase often suggests there may be unexpected obligations or duties involved when getting something for 'free'. 
When they said I won a free vacation, I discovered there's no such thing as a free lunch – I had to attend promotional meetings.
Pro Tip 2/3Cynical Expression
This saying is used to express skepticism about freebies, hinting that there's always a catch. 
He laughed when I expected free advice, saying there's no such thing as a free lunch.
Pro Tip 3/3Not Literal
The phrase is metaphorical; it's not just about food but applies to any situation involving a 'free' offer. 
They give free software, but your personal data is the price—there's no such thing as a free lunch.