Pricing in MD will vary. Baltimore pricing has gone up recently, I don't know Silver Sprint or Olney or other areas in MD.
for context, my youngest is 7:
I paid about $1000 a month for my daughter 6 years ago for full time hours (~40 hours a week). We had a babysitter in our house who we shared with a couple other babies. Prior to that we sent to a local frum daycare (that closed) and paid between 700 and 800 a month (it was by the hour, so yom tov months we paid less).
I think the going rate now is about $8 an hour in a group, but paid on a monthly basis.
The amount per month may be dependent on the hours used. Do you need full time or part time?
Do you want to share a babysitter in someone's house? Do you want to go to a babysitter's house? Do you want to try to get into a legal daycare? Do you qualify for vouchers?