Payments are always taken on the 3rd of each month. When you sign up you will not pay straight away, instead you will be charged on the first 3rd of the month after you join. For example, if you join on March 1st, you will be billed on March 3rd and receive the March box. If you sign up on March 16th, you will be billed on April 3rd and your first box will be the April box.