It’s a free country
Definition 1 of 1
Pro Tip 1/3Sarcasm Warning
The phrase can convey sarcasm if someone does something unusual or annoying. 
Oh, go ahead and play your guitar at midnight, it's a free country, isn't it?
Pro Tip 2/3Defensive Response
Used to defend one's actions when criticized, emphasizing their rights. 
I can dye my hair green if I want to, it's a free country.
Pro Tip 3/3Informal Use
The phrase is informal, best used in casual conversations or discussions. 
You can't tell me not to eat this in class, it's a free country.