I've been following this thread with interest as I have a small shop in addition to my longarm business, and it's always a guessing game as to what will sell well. When I read the original question, my thought was - she's going to get as many different answers as there are people responding to the question
. And with the exception of the trend of people looking for white/cream/neutrals, I think I was right. My experience is that what sells the best is the line that you make samples from. I can take a piece or line that isn't selling, make a sample with it, and it will usually fly out the door.
Good luck with your new venture!