What’s the best shipping option?

What have you found to be the best option for shipping large and/or heavy objects. I've had a few requests for items off the Duster I am parting out. Things such as the hood, window glass, k-frame, springs, etc. are not very suitable for boxing up and dropping off at the post office.

I would like to hear from some of you with first-hand experience, either as a seller or buyer.

Thanks,
Jerry