What are the meanings of "Taobao free trial" and "Taobao post trial" in Taobao?

Free trial means that after you apply, if you can be drawn by lottery, then you can try this thing for free. Paid trial, that is, you can get it by paying some postage. After using it, write something about the trial experience. One-dollar spike is divided into time periods. When it starts, when it ends. You have to have some skills to catch this.