L.,
I agree with what Mama Mia said - don't pay for anything at this age! Even though it's chilly out, you can still get out for strolls. Walk, wander and watch the world go by. The Mall is perfect with all its hidden gardens between and within the museums. Lots of large open spaces in all of them. Natural History has the Discovery Room too. I haven't been to the Portrait Gallery since it's reopened but it used to have a gorgeous garden in the middle.
In the travel section of the bookstore, new or used, look for the books: DC for Free and DC for Kids.
... oh yeah.. get a MacLaren stroller - it's the best umbrella stroller ever and worth every cent. Mine is over 11 years old, has carried all five of my children (thru the years), and has been around the globe many times. If you hike, the Kelty backpack is brilliant.
Good luck!
--M.
www.SlumberPartiesbyMariaElena.com