I typically charged .01 a word. So, 1k word stories were $10, 10k word story was $100, and so on. Most professional freelance writers charge around .02-.03 and big publications will often pay up to .05 per word. It doesn't sound like much, but it adds up quickly over a large story and if they want more added in, then you have an easily justified reason to ask for a bigger price.

As for whether you think you're good enough to charge a certain amount, I'd say that's less a case of how good you are as a writer so much as how reliable you are as a business party. Your work may not be the best, but if you deliver it on time (have a deadline and stick to it), engage with your commissioners (samples, progress updates, basically letting them know their project matters to you) and be willing to change the work if they're unsatisfied (but still make sure you get paid for extra work as mentioned above) then they'll come back to you again and again for being reliable.

$1/200 words actually sounds pretty good to me.

I usually charge 5-10€/1k words, depending on what stuff the person wants in it. I would not go above 10€($) per 1000 words, then ppl start to complain. If you get around the 5$/1k words, ppl will want stories a lot from you, including me :D

I'd do like $7/1k words and feel good about it.

$250/5 words

done.