Should I keep my truck or sell it and get a different one?

I'm 17 and I just got my first truck. It's a 1995 Ford F150 (5.0 V8). It's sitting in the garage right now because I can't afford to register, insure, and fix it (it needs quite a bit of work). I didn't buy it. My dad gave it to me. I absolutely love this truck but, I think it'll use too much gas. I had my grandfather's truck for a few days and I think it got pretty decent mileage (Ford Ranger) but, I did have a lot of things to do and places to go (so I had to put gas in it a couple times). I feel like if I were to get rid of the truck and get something else but, I feel like I'd regret it. What should I do?
Added (1). I was thinking about doing that because the body is extremely rusty and is way too expensive to fix. The frame might possibly have some issues.

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