When you purchase a Month-To-Month plan, you pay for Web TimeSheet after each month of usage, with no commitment required; you can cancel at any time. Each month you will the billed according to peak usage. This means that, for each product, you will be charged based on the count of maximum number of license seats that was assigned during the billing period.
For example:
If you use 50 Expense seats for the first week of your usage month, and then remove 10 Expense seats (leaving you with 40 Expense seats for the remainder of the month) You will be billed for 50 Expense seats that month.