Unlocked versus Jailbroken – What's the difference?

Unlocked versus Jailbroken – What's the difference?

My friend wanted to sell her iPhone 4 on eBay, so I started looking around to see what kind of value they had. Just as with any eBay auctions listing cell phones, I ran the gamut of seeing unlocked phones and non-unlocked phones, while others were listed as jailbroken phones