If you follow through with this crazy plan to charge so little, you will hit a point of resentment toward these parents, apthough it is your fault for offering to go so low, they too should not be attempting to take advantage of your time and services. not to mention, they will spill the beans to others and before you know it you have a bundle of cheapskates knocking at your door. unless your quality of care is low, you deserve more and anyone bringing their child to you should be willing to pay more. (i have to say though, not many parents will argue with a lower rate)(although the great ones do) This is what I would do:
type up all your contracts, and get your place set up as a daycare (if not already) place an add for more kiddos IF you want to. Then? give the current parents you have the contracts and let them know they will go into effect with in a specified time frame (one month or so). You need to treat everyone the same, family, friends, rich or poor. YOU have a business and you need to act like it....you are not some wealthy chic who loves kids so much that would just prefer to offer care for free, you are doing this for a living so make these parents see that.
remember: 1. the cheaper your rates, the cheaper people will treat you!
2. business is business, not friendship.
Good Luck! and don't forget...you are worth the pay and anyone who doesn't think so..isn't worth your time!