'Cash purchases' means any payments you make for business supplies which are not made on account (so you pay for them there and then).
As you provide services rather than goods you are unlikely to purchase large amounts of supplies on a regular basis. However, if you include meals and snacks as part of the childminding service that you provide then you will make regular purchases of food items and ingredients for your business. You'll also spend money on consumables like toilet paper, tissues, moist wipes and from time to time you'll buy play items like drawing paper, paints, crayons and other toys.
Even though you and your own children may eat your meals at the same time as as the children you look after, it is important to keep a separate record of the cost of feeding your clients' children. This cost is a business expense. When you fill in your cash flow forecast, make an estimate of the monthly cost of any food that you will purchase for children left in your care.
Remember to keep safely all the invoices and receipts for purchases of food and other items such as cleaning materials used by your business, even if the amounts are small.