It's all about LOCATION LOCATION LOCATION. There is a reason, I am sure. What you need to do is research the area for yourself. Go online and pull up city searches for the general area, and get statistics on the area. What are the income levels? Where are the jobs? What are the major employers? If you have children, start looking at school district data online. Most schools now have websites and TONS of information online, from when school starts and what days the kids get off to their rankings/stats at a state level. If the site you're looking at doesn't have that, google "PA school district rankings" and you'll find sites that will tell you graduation rates, PSSA scores, etc. FINALLY and most importantly you MUST go and see the area for yourself. Something that looks good online might not appeal to you at all, and vice versa.
Where I am in east/central PA many of the most rural areas have very reasonable/cheap prices. The closer you get to the cities, the higher the prices. I hope this helps