I made ramps for winching/driving wheeled stuff into my trailer. I had a piece of galvanized C channel that was approximately 10" wide, 2" tall, and 7.5' long.
I cut it in two pieces. I welded lips to each piece, such that I can use them in two ways: C up and C down, sort of. So that I can either drive stuff with wheels constrained by C, or alternatively place them upside down and put, say, a big piece of plywood over it.
These ramps can also be used to drag material my handling cart into the garage over the "step" in concrete.
The C channel is from 1/4" to 5/8" thick (see pictures) and was cut with a Hypertherm Max 100 plasma cutter.
I used this channel because I had it. I realize that it is too strong for the application (meaning that it is too heavy), but that's what I had -- it was a garage sale style purchase.