How much would it cost to fix up my truck?

I'm a 17 year old male and I'm getting my first car. It's a 1995 Ford F150 extended cab. I really like it and I've always wanted an older square Ford truck. I've always loved cars since I was little. I really wanted to restore something and this seems like a good opportunity. It's really rusty. Some places to notice rust are
-Behind driver and passenger doors
-Front fenders
-Bed (I plan to get a different one)

The wheels, paint, and interior are in great condition. It runs great. I want to do whatever work I can, myself. How much would it possibly cost to fix all the rust and paint where it's been repaired?

Try looking for used body panels that aren't rusty at online junkyards. They will ship just about anything. You can probably learn how to replace body panels on your own. That may be cheaper than having a body shop fix rusted out panels.