The cost for painting a house's interior varies quite a bit. How big your home is and what kind of paint you want will be big factors. Even with those factors set, different contractors have varying rates. If I were you, I'd get quotes from a few of the contractors in your area. http://www.apcne.com/commercial-painting-contractor
Painters have a variation of costs according to rooms painted, types of paint used, and the time it takes. Each one is different in what they'll charge, so I'd recommend getting a few different quotes before deciding. You want to choose the one that will be the best fit for you and your home. http://www.intownpainting.net/aboutus.html
Painters will give your free estimates. The cost can vary depending on why you are painting- is it just for you, are you planning on selling, etc. That will impact your cost in regards to quality of paint, etc. I have a few folks I can recommend. Feel free to call at 404-483-7816
If we take the average size home at 2200 sqft, then you should budget $200 for paint if you want to do it yourself or $2200 for professional painters. Of course, you can easily double or halve both figures if you choose different quality paint or painters.