There may be a few things going on for the discount code not to work.
Reason 1: Most sale items have already been discounted so you don't need to enter a code to get the sale price and in most cases because of this, further discounts won't be accepted unless stated.
Reason 2: The discount code may be expired due to running past a sale period or a time in which the discount was advertised.
Reason 3: You could be entering the code incorrectly. Remember that any discount code entry is case sensitive meaning a lower case "m" to a capital "M" will create an error if not the same as the discount code provided. It would be best to copy and paste the code for accuracy.
Reason 4: There could be an error in the system. If this is the case and you think there is something wrong, please email mike@totalmanperformance.com and we can get it sorted as soon as possible.