I just got a few wooden crate pallets for free today from a neighbor who is having tile laid in the kitchen. The base is solid thick boards and strong. All looking new. Going to take the sides off for the platform. Then use outdoor porch epoxy paint to them. These will do well for keeping the 3pt hay spear nice off the ground in the barn.
One of my brother in laws in Canada worked where they threw out several pallets a day. After work he would knock them apart and put them in the trunk of his car. On weekends they took them to a lot in the woods they had bought. They'd scab the 2x4 side rails into 4x4's for floor joists and studs and the 3/4 tops became flooring and siding. About the only lumber they bought was for rafters and plywood for the roof. Most of the doors and windows were scavenged on trash days. By the end of the second summer, they had a pretty decent little camp. After a few years they vinyl sided it and sold it at good profit.