Pricing strategy for advanced amateur?

Dear business owners,

I am an amateur photographer who wants to become a pro some time in the future (maybe only part time).

In the mean time, I would like to grab spontaneous opportunities to gain experience.

I currently don't have the time to market myself or take on regular assignments, but I don't want to miss the occational job when asked by colleagues or friends of friends.

What would be a clever pricing strategy for these occasions? Can it only be "all for free" or "full pro prices"? Would it be stupid to get something inbetween, possibly hurting future business?

Best regards,
Sven

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Sven Hedlund
http://www.svenhedlund.se