My daughter usually gets $25-30/day when she does this for the neighbors' (one dog). She goes over first thing in the am, lets the dog out, feeds/waters her. Then she stops by at least twice during the day to let her out for a run around and playtime. Feeds/waters around 6pm, then a last time out ~10pm. The day the neighbors are to come home, she gives the floors a quick sweep & mop, vacuums the carpet and wipes down the counter. She also makes sure there's fresh milk, juice and bread in the fridge.
Two dogs... I think a bit extra would be in order.
ETA - she also wouldn't dream of not picking up after the dog.