I'd just like to make a couple of comments after reading this thread. The fact that "sample" appears on the image does make it appear to be a proof, therefore copyright issues were not out of the question. And copyright protection should be honored in this business. This is not to say that you did not put "sample" there yourself, and it does not infer that it has a copyright (although it would seem suspicious if it didn't).
As per the question of why so many people have looked at this thread, but didn't offer an answer could have different reasons as to why they did not. Some people simply read the threads, and many are not members of RP, so do not have the option of replying without becoming a member, which might not be their cup of tea. Others, like myself, do not do this work for profit, and couldn't offer a good answer even if we lived next door to you.
Now on to the pricing question itself. It has already been stated that different locales would likely have different going prices, and that is good advice. If you have a business, you should have a business plan that would include pricing practices.
You mentioned the wear and tear on your eyes. It's this simple. If you want to do the work, do it at a price you can live with. If your eyes are more important than what she wants to pay, simply refuse the job. If you are interested in what others in your area are charging for such a job, do your homework. It's not that hard. Overhead comes into play, and everything should be counted including ink, paper, other supplies, mileage (if appropriate), any insurance, and all other costs of doing business.
I don't want this to sound like a shot against you, but more as a help understanding why you're not getting more feedback, and why the copyright issue was brought up.