The Apple Security Research Device (SRD) Program allows security researchers to find and report vulnerabilities in iOSs security. If you join the program, you can get a free iPhone for free by signing up for the initiative. Apple says that it is not personal use, shouldnt be used as your day-to-day phone, and is intended for security research only. But if you do use the SRD to find an iPhone vulnerability then there could be some not insignificant amounts of cash to be made.”]
Source: https://grahamcluley.com/free-iphone-apple-bug-hunters/