If your going to offer spray tans cheaper on a day of the week I would recommend doing them on one of your quieter days, like Monday or Tuesday...most people want tans for the weekend so will be coming to you anyway on a Thursday or Friday so there isn't really any need to discount on what would probably be your busier time of week.....Obviously, only you know what your busy times are, I would just say don't do yourself out of full paying clients when you don't need to xx