I did a lot of researching sharpening services on the internet and found that I would love to charge prices that are competitive in San Francisco, but can't in the Pacific NW.
And I would go broke charging rural Midwestern prices.
Up here prices start at free at the local supermarket (yikes!)
You get what you pay for.
I charge $5 for a standard 8" - 10" chef's knife and haven't gotten many complaints. I'm high compared to local knife shops, but I come to their place of business or home so the cost difference is justified.
Plus I specialize in professional chefs who appreciate a sharp blade and usually don't have time to spend matching the quality of the work I do.
You need to find out what your local competition charges.
Hope this helps.
NotsoDull! Mobile Sharpening Service
"Life shouldn't be dull."