An employer 401(k) 'match' of 50% up to 6% of salary means what for an employee earning $60,000?

A 50% match up to 6% of salary on $60,000 means the employer will contribute $0.50 for every dollar the employee puts in, up to 6% of salary ($3,600). So the employee contributes $3,600 and the employer adds $1,800. That free money should never be left on the table.