Great piece -- as a freelancer myself, I identified with your pain. My lowest freelancer moment came writing for an online city guide that was paying me $35 for 400 word restaurant reviews with no food budget -- I was supposed to visit the restaurant and describe the feel of it, but not actually eat anything. When I had written about 8 of these things over about 4 months, I said "what with the price of gas, can you bump up my rate please?" The editor said she would give me an extra five dollars.
Thankfully, I quit writing for her and found greener pastures -- but honestly, the GALL of some people!