1994 Mazda 929

1994 Mazda 929 248,149 miles. I was driving on the highway when I noticed the car was kind of jerking while I was driving. When I got off the highway I stopped at a light and while I was stopped the engine died. I tried to restart it but I was panicked since I was in the street and forgot to put it in park. I had some people help me push it out of the way and waited for a friend to arrive. While I was waiting I tried starting the car and it took a second to turn over but then it would. My oil light came on and so I turned it back off. When my friend arrived we went and bought oil and I put it in my car. Then when I tried to start it, it started fine. I still didn't want to get back on the highway to get home, though, so I was going to leave it. Then my friend tried to start his car and it wouldn't turn over. He just had a loose battery cable or something but before we figured this out, we tried to use my car to jump his. While our cars were on and connected mine started sputtering but not dying. It ran for this like 10 minutes and then died. I would try to restart it and give it some gas and as soon as I let off the gas it would die. Or it would stay on for a few minutes, then die. I left it there, then decided to to drive it home the next day. It started after a second, then went along fine. But while I was driving on the highway, it started making a loud grinding sound and I realized my rpm was way too high for how many miles I was going. I was going 60 and my rpm was over 4000. I let off the gas and was still only going 60mph. Then I slowed down to about 40 to make sure I would be able to slow down if I needed to. When I tried to get back to 60mph the car make a noise like something just breaking apart and the car just started losing acceleration and died. It would not restart again and when I popped the hood, there was a small amount of white smoke coming from under the radiator cap. I had it towed to my house before I take it to a shop. It seems like everytime I it to this place, they always charge me a roundabout price of $1,000. I'm afraid to take it in again cause I'm sure they'll charge me at least $1,000 no matter what's wrong just cause I'm a girl. What are the possibilities of what's wrong with my car? Please help.