In your situation, I would sell and buy something in the 5-8k range. Think early to mid 2000s, low miles.
But unless southern maine's market is very different than the rest of the country, you should be able to get cars with a lot fewer miles than 150,000 in that $3-5k range. Be patient- most people on Craigslist either inflate the prices on purpose hoping to settle for a lot less, or are just clueless about the real value of their car.
Try telling your friends and family that you are in the market for a used car, you may be surprised by the number of people who knows someone.