Some tips on figuring out a price.
See what people are charging locally for similar service.
Find out what you’d need to cover your bills, housing, utilities, food for the family, equipment maintenance and replacement when the time comes, insurance, software upgrades, any marketing expenses such as paying for web page, business cards, advertising of any sort.
Figure an ideal of 20-25 hours of paid work per week. Another 15-20 hours unpaid for marketing – web pages updates, talking to potential clients about jobs, system maintenance, doing paper work, etc.
Take the number of hours of anticipated worked and divide by your above costs. That will give you a good idea what you need to charge per hour. You may find people are charging more or, often less (they’re giving away their serivces and will go out of business, the market is flooded with people doing the same work). Then you need to figure out how to get the price you need to stay in business.
If you need to charge flat rate, you need to figure out how long it will take to do a given job. Sometimes that takes experience. Many folks underestimate the time it takes when starting out.