Hi Lizz_O
The better options I’m aware of in the Northern Virginia area are listed in post #2 here.
You may even find that your “best” choice in the DC area is not even local but may involve an online purchase (you can see an example of a member here from the DC area that decided in the end to make an online purchase and why). Of course each person may be very different in which parts of their “value equation” are most important to them.
Whatever direction you end up going for your purchase … some good local testing and research on different types of mattresses and materials will either lead to finding the best possible local quality and value that meets your needs and preferences or at the very least provide some good guidelines for an online purchase.
Phoenix