Anything you buy used you can write yourself a receipt that has the date and place of purchase on it and the amount paid. This applies to things like from a garage sale. In effect what you are doing is transferring an item from personal to business as in you bought it and now you are selling it to your daycare. This also applies to things you have from your own children they have outgrown that you are adding to the daycare such as a highchair or playpen.