I do up their invoice and print out two copies. The invoice is for the next month and goes home the 2nd or 3rd week of the month. When I deposit and the clear their payment, I write "PAID, the date, cheque #" on my copy of the invoice. I then fill out a dollar store receipt book so the family gets an actual receipt each month for tax time. I like it because my copy stays in the receipt book, and holds all the receipts I ever write related to daycare for my own record keeping.