I put my paintings in a frame that I really like and include this in my fee. So far, I haven't had any problems with this and consider it part of my "art". On my website, I try to show framed pictures:
www.portraitartist.com/wells
I tend to buy inexpensive frames and put the painting in the frame as I finish it. Also, I use the oil colors from my palette to rub into the frame so it is completely compatible with the painting.