First, you need to find a bed that properly fits your truck. Sure, you can put one that is designed for another truck on your truck but this will look unsightly and may cause other issues later. Whether you buy a truck bed form a junkyard or a retail store that sells them brand new, check to make sure it will fit your model of the truck.
The first place you should consider is your local auto wreckers or  scrap yard s open today near me. You never know what hidden gem you may find amid the rubble. Often people will dispose of a vehicle without realizing the potential worth in it. Many would rather not invest the time and money necessary for the restoration of classic cars. That alone is a great way to get them to unload their classic on you. There is a good chance you will find an old car at the junkyard that has been left there due to age or missing parts. If restoration is what you plan, this can be a goldmine.
Obviously buying used can have a huge cost benefit. Unless you have a rare or high-end luxury or sports car, a salvage yard special will be between $25 and $50. Not bad compared to the cost of a new cooling system from your local dealer.
Make sure that your cut line avoids any doors for simplicity. Have a friend help you to pull the two halves of your car apart and set them up on blocks. Now head to the wrecking yard and find a car just like yours that you can cut a midsection chunk from.
A great alternative is the junkyard. Often when a car is totaled and sent to the junkyard, the spare tire is intact. Many have never even been used. So how do you find a great match there?
You know the exact places I am talking about. I am sure you have passed one or two and thought about how unsightly these places are. Most of them are covered by an outside fence but still you are perfectly aware of what lurks behind that fence. This vehicle graveyard is a precious source holding a plethora of car parts for your exact vehicle. If the insurance company can put these parts on your car when they repair it, why should it be any difference for you?