You are looking at two issues, accounting, and labor law.
Accounting: All T-shirts are expenses when they are handed over to the employee since you most probably will not recycle the old T-shirts of leaving employees. The payroll deduction of $ 50 is Debit: Cash Credit: Liability to Employees. Make sure that you maintain a record that identifies the account balance by each contributing employee.
Legal: I understand the company's motivation to ask for a "deposit" for the T-Shirts to give the users an incentive to hang on to the T-shirts and eventually bring them back. Otherwise, everything that is free tends to be abused. On the other hand, I could take the position that the company forces the employee to finance their own uniforms, and by putting a logo on them, forces them to render an advertising service for which they are not renumerated for. And last but not least, how much interest is the company paying on the money lent to them by the employees.
As an accountant, you should not only keep the accounts of your customers correctly but also inform them about existing and potential liabilities that you notice during handling their financial transactions.
I know, at first glance, it sounds like a joke. If you are a Controller of one of the major manufacturing companies, such "jokes" have become issues of serious concern and not looking out for them can have serious consequences.