I always buy high mileage cars. Always have. I use to have all kinds of troubles out of them. In the early 90's they started making something called Duralube. The first car I put this stuff in was an 80 model Dodge Charger with a 2.2 engine. I only paid $25 for the car, so I put this stuff called Duralube to the test. I put it in my car and drove it about 1000 miles and then I pulled out the oil plug and drained out the oil. I then proceeded to drive the car 100 miles, then I turned around and drove the 100 miles back. I put the oil plug back in my car and filled the crankcase with oil again. I then drove the car for another 2 years, and then gave it to a friend who drove it another 2 before he wrecked it, The same original engine and was still running good after that. Since then every car I have owned get a quart of Duralube as soon as I buy it. I haven't had an engine break down on me since. I have had a lot of other problems, but never the motors.
Duralube can be bought at K mart or Walmart for around $20.
I am just telling you what has worked for me. What you do is up to you. But $20 is not a lot to try. You waste more money than that with one movie.