When you get to translate the first paragraph as the customer asks you to do to see if it is good enough, you put your work in it. If he doesn't decide to take you on, you are not paid for say a 100 words...he might do the trick with various other translator and have the document done in 4 04 5 times paying nothing? How do we deal with this one paragraph translation for free?:

No free translation of one paragraph. As simple as that. If there should be a free translation, I would require a thorough feedback stating why I wasn't selected.