I've never given a discount nor have I felt compelled to. The siblings both eat, use supplies and require care. I don't think 'buying in bulk' savings should apply to a service provided which is already bottom of the barrel cheap anyway. I know lots of people do it, but that's just my opinion. I think Reggio made a good point....see if it's even necessary in your area. Is there high demand in your area or are you scrounging for clients and maybe an incentive like that would help things along? The savings you offer her may not seem like a lot on a day to day basis, but add up that loss over the course of a year or the duration of that child being in your care....it might actually curl your hair!