Weekends are tough. I started out doing some weekends just because I needed the income. Once I was stable I stopped doing them. I found I really needed the 2 days of quiet.
When I was working outside the home I was being charged an additional $5.00 per day per child for Saturday and I thought I was getting a deal! I'm in Ontario though, so that may not be usefull information. I was just lucky I had someone to take my kids on a Saturday.