Yes, you do really have to use your own money if your employer wants you to; this is perfectly legal. An employer may set any terms and conditions on, or requirements for, employment that it likes; those terms, conditions, etc. can include that employees have to pay for supplies out of the employee's own pocket. The law does not even require them to reimburse you--they can make you absorb the cost. Your recourse, if you don't like working for someone who does this, would be to look for other employment.