If I have a two man painting crew and live in Columbia South Carolina, do I need to have a small painting business license? Also, if I charge by spuare foot, not by wall, what is a good decent price?

You need more then a license. You also need liability insurance, you will need to register with the state as well as a few other things. I would recommend contacting your state to find out what the requirements are for a small business. Also check out your local Small Business Association (www.sba.gov) they are an amazing business resource for the small business owner. They has lists of what you need to be legal in your state. Best of luck to you.

Around where I live, the going rate for two coats of paint is around .70 cents a square foot. That price would not include the paint product used. It also does not include applying a primer if it is needed.

You will want to charge significantly more if you have to do a lot of repair and if the surface area to be painted is not absolutely flat but textured.

To find out what painters are charging in your area, you might consider just calling around to see what others are charging. You don't have to tell them that you are also a painter. Just give them a hypothetical painting scenario. Room measures such-and-such and the walls are all flat, no repair, etc. You probably could also find out what the going rate around where you will be painting by asking someone at store that only sells paint products.