In the $150-350 price range, I've been pretty impressed with Nikon and Vortex. I actually currently have a $180 Nikon ProStaff 2-7x32 mounted on a $1600 AR that I set up specifically for shooting 100-250 yards. Some would call that blasphemy, and I probably will upgrade at some point...but I really have no complaints about its performance.
I'm sure there are plenty of other good options, but those two in particular have impressed me for budget options.
"The Future is Unwritten"