We have paid about $50 a day to have a teen/YA stay overnight at our house with our dogs. We always work out the price up front/in advance so there are no surprises. I've found kids don't seem to negotiate, and usually agree to whatever I offer. The $50/night is still considerable savings over either a kennel or a professional service. Since we know them, we usually ask in advance what their favorite snack/breakfast foods are and stock up on some of those. It would depend in the individual situation. Usually the sitter goes to school/work, and eats dinner with their family, so stocking dinners isn't necessary.
I will say that Trail's End is awesome for dog walks/potty break visits. They offer overnight also, we just aren't comfortable enough for that yet.