What year/model truck? Several aftermarket companies make protector plates for the front of the bed. I have seen stainless steel and aluminum diamond plate products. These seem to be more common for older trucks (perhaps before factory bedliners became common) but there are some options for newer models.
I owned my last truck 6 years without any protection in the bed. In that time I built 3 barns and did many other projects, and moved a lot of building materials, blocks, concrete, etc. Plenty of scratches in the bed but no rust and no damage to be concerned about. So my advice is to not worry about it. Or if you are worried about it, get a bed liner (now or later, after it's already scratched up). Anything between those two extremes is bound to be inconvenient and a hassle for one type of load or another.
My new truck came with a factory spray-on bedliner and I have to say I like it. The texture is really perfect, not too slippery and not too grippy. About like regular paint.
What I'd really like are some stainless steel or aluminum caps for the bed sides (plastic onces from the factory are wimpy) but nobody makes them for new trucks anymore that I have found.
