It's really very simple. Buy donor parts or a donor truck that's near you. Better metal, better fit, no shipping, cheaper part price, fun to search and find and it recycles and you can practice welding on the scraps. If I'm counting correctly that's a win win win win win win win win. The deals are in the trucks with no motor, no trans, no title, rusted in places, dented in places and missing stuff you don't need anyway. I've never purchased new sheet metal for TF. I've had many.
I would like to know what "a lot" is and what pieces are you talking about?.......and for the 900,999th time to new guys: Please! EVERY TIME you start a question post............state the year, make and model of truck.
P.S. I know I used "and" too many times. It was done for dramatic impact, visual acuity, maintain subject anticipation and situational awareness. It's high level writing stuff. The commas were left out between "win, win.." for the same reasons.