It typically depends on how many pets, how many visits per day and what is expected. Special circumstances like medication or special care can also add to the rate.
We have five cats and a pug who must go out twice a day. She scoops the three cat boxes once a day, brings in the mail and walks the dog, checks on the food and water, but nothing out of the ordinary. Her visits typically take between 30-45 minutes and there really is nothing to do for the house (we live in a secured condo). We pay $15-20 per visit.
That's probably on the high end due to the number of animals, but in our experience the range starts about $10 per visit and can go up to about $30 if there are a lot of special instructions. That's pretty typical here in Salt Lake.
We used to have a young married college couple pet sit and they were much cheaper ($25 per day for both visits and everything) but we also ran into some problems with their reliability. I'm a big believer in paying for peace of mind. This new pet sitter is responsible, reliable and very responsive to our concerns and requests. She follows our instructions to the letter and our pets are happy and healthy when we come home. That is worth what we pay her.