How much to charge for social media consulting?

[James]

Hi,
I'm 15 years old and very in touch with social media, I earn money from YouTube Videos from Google's Adsense, and am on all major social media websites and use them both personally and from a business perspective myself, to give you an example of my knowledge.

A friend's parent is looking into Social Media for their small business (just them at the moment employed) and wanted me to provide Social Media as a way to connect with customers / fans of the business, and wanted to know how much I charge.

I am looking at a flat rate to start off, then a monthly fee, I don't want to charge per hour as that could be difficult to work out.

Basically, I'm not too sure on how much I should charge, I would like to make a decent amount but also a friendly one.

If anyone could help me it would be much appreciated

Thanks