You have a few options here.

1. Find marketing consultants or local marketing agencies that are looking for interns through local job boards and through LinkedIn.

2. If you already have LinkedIn, pull off a list of email addresses for your contacts and then write them all an email explaining pretty much exactly what you have explained above. Ask them if they need help or if they know anybody that needs help and let them know you will do some work for free to gain experience.

3. Sign up as a freelancer on all the freelance sites. Though you might be worried you don't have enough experience, you still have more knowledge than the average person on the street because you're investing your time in learning.

You can charge a lower rate than other freelancers in attempts to win business and to reflect your own experience.

4. Do you have a website yet? If so start writing posts about Facebook Advertising. Write about the things you are learning, your tips, the obstacles you are facing.

Now, you have posts to promote. Eventually, perhaps, you have a blog you can monetize.

Also, when you sign up for hosting for your website, some hosting companies will give you coupons to spend on services like Facebook Advertising or Google. So, if you have a website, go check your cpanel as there may be some Facebook Advertising coupons in there for you to get started.

5. If you have any related experience, start by winning business in this area first and then gradually sell in Facebook Advertising as an additional service. For example, if you are already comfortable with organic Facebook Marketing, look to win business in this area first and then weave in your Facebook Advertising service at a later date.

Good luck!