How much should you expect to pay a professional to paint the interior of your home?

It really depends on what you need to have painted (walls, ceilings, trim) and what kind of prep work will be required. Check out this site for a rough idea.

Cost of Painting an Interior - Get Prices and Estimates - CostHelper.com

Yes, as mentioned above, it does depend on a number of factors. The type of surface area to be painted also makes a difference as to the price one will pay. For instance, walls that are perfectly flat as compared to those that are textured in various ways. If someone is spraying the paint as opposed to brushing and rolling will also make a difference in the price as will where the home is located because the prices from one region to another can vary greatly.

Where is the home located and what kind of surface areas is it that you are asking about a professional painter painting, please?