Covering the cargo section of a truck isn't that difficult to accomplish; you have several options. However, choosing the right option can take some time. Many truck owners use tonneau covers, which are relatively strong covers, often rigid, that cover the bed of the truck completely. However, sometimes a good old tarp will do the trick -- and maybe do it better. Tarps have quite a few benefits, and many trump the tonneau cover in terms of convenience.
Which will be lighter, a plastic tarp or a metal tonneau cover? Granted, there are some light tonneau covers out there; aluminum, and even canvas on a roller that's installed at one edge of the truck bed are options. But a tarp is very lightweight and doesn't take a lot of strength to position. If you're not the strongest person, even a lightweight tonneau cover can be awkward to place over the bed of the truck. Tarps, though, are easy even for people who are weaker than others.
Easy to Remove
Just as the tarps are easy to put in place, they are easy to remove. You don't have to worry about ensuring a rolling cover rolls up properly or that the one-piece, rigid tonneau cover doesn't hit anything as you lift it off. With a tarp, all you have to do is pull and then roll into a bundle. If you need to clean the tarp, you just need a clothesline and a dustcloth, plus any cleaning solutions appropriate to what you were carrying.
Tarps are generally cheaper than anything else. Even when you include the cost of ropes or ratchet straps to keep the tarp in place, you're not looking at a giant store bill. Good tarps aren't totally cheap -- you get what you pay for in many cases -- but they're generally cheaper than a reusable tonneau cover.
Tonneau covers that are removed in one piece and that are rigid are difficult to store. You need enough room to store the entire thing, and it will take up space. A tarp, though, once it's clean, can be folded into a small package and stored in a cabinet. The only thing you have to be aware of when you store a tarp is that insects can crawl into the folds if you're not going to use the tarp for a long time. Store the tarp in a bag that you can seal up.
Tarps are easy to find, and you can get ones that are built to the specific dimensions of your truck bed. Talk to truck accessory dealers, such as Lehman Awning Company, to see what they have in their inventory and what they might be able to order for you.