If you are looking for just an extra set of hands you mind find some very capable 13-15 year olds that are too young to get a "real" paying job which means the wage would be less. Babysitting does not pay minimum wage so look for what parents in your area are offering when looking to hire a highschool student to look after their kids for the summer and go from there. You might be able to reduce the hours to only needing them half a day and paying them by the hour. I was lucky in that for many years I had my own kids that I could make use of in the summer and it worked really well because I have a child with intellectual disabilities and while she was slow at many things academic she loved the kids, was great once she learned a routine and they loved her back. I would never leave her unattended with the kids but she was those extra hands and eyes I needed. I paid her $50 a week - I know cheap deal.