Why are Babysitters often paid less than min. wage? Is this acceptable?

In trying to set up a full-time babysitter for our child that will be born in a few months, I received an hourly quote of $8. This is from an unlicensed lady who will watch my child only, but that I know personally and feel more comfortable w/ her than w/ a daycare center. This made me start thinking…. a few years ago I babysat four kids ages 1–12 yrs. and made $6/hr. Has the babysitting price gone up that much in 4 years? Or is this lady overcharging me? What do you guys pay for babysitters? I live in Mississippi where there is no state minimum wage laws, but the national minimum wage is currently $7.25. I am pretty sure it was more than $6 four years ago. Was I being taken advantage of by being paid $6 to watch four kids, or is it typical to pay babysitters less than minimum wage?

**I think I should add- she will keep him in her home and have a car seat provided by me, so she can run her normal errands throughout the day if she likes. Just wondering if $8 is fair, and if so I am willing to pay it for my peace of mind!