The wage payment requirements under the Act for monetary wages specified under its provisions will be satisfied by the timely payment of such wages to the employee either in cash or negotiable instrument payable at par. Such payment must be made finally and unconditionally and "free and clear." Scrip, tokens, credit cards, "dope checks", coupons, salvage material, and similar devices which permit the employer to retain and prevent the employee from acquiring control of money due for the work until