Uniforms - professionalism at what price?

[Stonehenge]

I have a question for those who have uniformed employees -

All of our employees wear uniforms. Khaki pants or shorts, with a logoed t-shirt. I also provide 1 hat (Panama Jack style or ball cap, also with logo).

I give each new person 5 new t-shirts, a new hat, and reimburse $15 toward the purchase of pants (up to 5 pair).

The problem is, with some of the summertime help you get, with turnover being high, it gets expensive spending $120+ on employees that are only with you a few months, and never return the following season.

What are your policies for uniforms? Who pays what, what quantities, do you have probation periods before giving unis, etc...