I have worked with several newbie freelancers lately, and it breaks my heart that many of them took unpaid work on the promise of "getting their name out there."
Your time and skills are worth money. Whether you're an old pro or a newbie, your time and skills are valuable. Don't fall into the trap of letting people convince you that because you're new at something, you should work for free. Take a low-paying gig to boost your portfolio, fine -- but unless you're volunteering your work to the local homeless shelter, don't work for free.
When you value yourself, others will value you more. Plain and simple. Human beings have that innate understanding that "you get what you pay for" -- and clients don't often put a high value on free work. Besides that, as you grow in your career, the higher you raise your prices the higher caliber client you will attract. Higher-paying clients, believe it or not, are typically easier to work with and value your services more.
I'm sure there are exceptions to this rule -- but not many. Value your time and skills, and your clients will value them more.