I feel like we taught our kids to drive the cheapest way possible. They studied on their own for the learner's permit test and practiced driving with a parent in an empty school parking until they were ready for the roads. Then they drove to and from school every day, with parent in passenger seat. In summer, they drove to/from work every day, again with parent in passenger seat. So I think you need to find someone with a car who is willing to act as the parent. I bet a retired person at a local church would volunteer to do this. Just call around and ask if they will advertise your need in the church bulletin.
We live in PG county and use Leap Driving Academy in Greenbelt/College Park for online class and 6 hours behind wheel. I think you can choose to just pay for the online class.
https://myleapdrivingacademy.com
I know you said you were in Rockville but sometimes things in PG are cheaper.