I know I am a little old fashioned, but when stores stopped using price tags and started using only bar codes I got really nervous. I keep post-it notes in my purse. When I am shopping, I write the price per yard and the amount of yardage I need on the post-it and stick it to the fabric. That way, when each piece comes to the cutting table, there is a double check. It has saved me lots of embarrassment. Sometimes customers move the fabric around so it is on the wrong table, sometimes it is input into the computer wrong. With the post-it, it reminds both me and the cutter to check twice and only cut once.
I do the same thing with groceries, and any other time I am purchasing things in a bunch. I also keep a notebook of who charges how much for each item. That way I can compare 'sales' or deals with regular prices. I very rarely get anything at regular price. This is really nice on fabrics and doll parts. I know what I spent and that helps me know what to charge.