I sell my stuff and I used to clip a small piece of each fabric and staple it to a sheet of paper. I used one sheet for each purchase. If I only bought 3 fabrics that day I only had 3 pieces on that sheet. Or if I had 10 fabrics then that sheet would have 10 pieces of fabric. I cut them about an 1" sq. I also stapled the reciept to that page so I had a record of where I bought that fabric and when. I kept these on a clipboard.
I like to know where I bought something so I can start looking there when I want more of it.
I stopped doing it because it is a lot of work and I just got tired of doing it. but I should go back to it. It really helps to know where I bought that fabric I liked so much. I tend to find favorites and use them alot. When I can't get that favorite anymore it is wonderful if I run across them somewhere else later on.