Babysitting/nanny?? Rate

Just moved and was thinking of a way for me to go back to work. Dont want to work every weekend only family time. Will if have too though. Boyfriend leaves around 5 to get to work doesnt come home till around 6 I'm a Cna and was thinking if we could pay someone to come watch the kids 3 times a week from 230-6 just till he gets home maybe sometimes start dinner some nights not sure, have a 4 yr old and a 4month old. How much would u pay someone 3times a week to watch you kid total of 12 hours or so a week? The shift for cna is 7-3, 3-11, 11-7.