Difficulty: Moderately Easy
Step1
If you know of any photographers that have just purchased new equipment ask them if they need a test subject. Many people have received free headshots this way.
Step2
Think if you know any photographers just starting out. Family friends, relatives, photography students are all good resources. Ask them if they are building their portfolio and if they are looking for test subjects. Most likely you will get them to do it for free if you ask in this manner.
Step3
If neither of those tactics works then ask the photographer if they’d be willing to do a trade. Hair cuts, PR, voice lessons, web design are all sufficient trades.