Big pipe value question

My partner's brother is a big cheese with the local pipe fitters. When they end a job and are throwing stuff away he calls her. We ended up with some "pipe" a while back. One of the neighbors wants to barter some dozer work for some but I have no idea what to even call this to find its worth. I have a feeling it's pricey stuff. Here's what we have:

There are two pieces of steel pipe 35 feet long. I don't remember now, but the inside diameter is greater than 24 inches. I want to say it is 26. They are half inch thick wall steel, straight pieces with some kind of baked on white paint on the outside. We're talking heavy mamas that it took two big tractors to get them rolled off the trailer in the pasture.

There are three pieces of the other - two 12 footers and a 24 footer. This is black plastic, 24 inch inside diameter and one inch thick walls. It is suppose to be stronger than steel and sure is heavier than it!

We had no idea what we might do with it, but culvert crossings in pastures was our main thought. We sure weren't going to pass up free culvert size pipe. I just don't know how to "price" it for trade in work. Arlo isn't going to let me just give him some. It would be nice to know it's value just out of curiosity, anyway. It is big culvert size but isn't thin or galvanized. I can post pictures after I get time to stop at the pastures. We threw them in the low spots in two pastures so they weren't an eyesore. I was so shocked to find that the plastic pipe was twice the weight of the metal. I always think of plastic as breakable and cheap.

Side note - he told me that if we wanted to join two of the pieces of plastic pipe he had solvent that would melt them together kind of like pvc cement. "But when you cut them you have to use a chainsaw with no bar oil. The oil keep the solvent from working." I kind if wanted to ask if I could borrow his chainsaw for a minute.

Oh, to have a job where you use other people's stuff to do things like that!

The steel pipe sounds like coated line pipe, there should be markings on it somewhere and if it is pipe line pipe it will most likely have the following specification on it ''A234 WPB'' and then some pressure rating numbers like ''26 X 500'' if it is 26'' 500 psi pipe, if it is only 1/2'' wall it is probably not 500 psi but that is just an example. It will be one heck of a good culvert.

If you don't have a use for them, I would value them at the current scrap price. Estimate the volume of steel from the pipe dimensions and multiple by .283 pounds per cubic inch for steel. If the seller thinks they are worth more, he can still sell them and pay you in cash.

My driveway culvert is some pipe cutoffs used for pilings to build a Mississippi river wharf.
About 14 or 16 inches around and some heavy stuff. I had to cut it into about 4 foot lengths just to get it light enough I could load into my pickup.
I figure if a air hammer can beat on it for a hour and there is no visible evidence of damage nothing I can do to mess it up.

The black plastic sounds like HDPE pipe. We used 24" for a mainline water pipe for the city. Lengths are welded together with a machine, ends trimmed, heated and pushed together as a weld....James

https://plasticpipe.org/pdf/high_density_polyethylene_pipe_systems.pdf