Here's an example of what you can get in Old Town Manassas. Way under Tobias' budget. Positives are 1/2 mile to VRE/Amtrak station and the historic downtown area. Negatives are the commute and apparently lower rated schools. While it would be a long train ride into DC, you are allowed to eat on VRE so you could use that time better than, say, on Metro.
I really don't know what it means, though, that the schools are "Below Standard". My guess is that's based on test scores? And my guess is those are lower because of a high foreign born (mostly Hispanic) population without strong English skills? You can read things online about gangs, but I don't know if that's mostly just racism or not. I'm sure much of Manassas is still pretty redneck and plenty of people who don't like all the darker skin folks who have moved in over the years. So that would be another negative, too.
If schools do seem like a problem, I guess the cheaper houses could leave enough room for private school.