These are called U-Channel or U-Style posts because in cross section they are U shaped. The ones called T-Style also work. They usually cost less than $5.00 and are available at building supplies and garden stores. You just pound them into the ground. Depending on how hard your ground is, you might need a sledge hammer. At right is the small 3 pound sledge hammer that I use.
Get the thicker, taller stakes. If necessary stand on a chair or stepladder to be in a good position to reach the top to hammer on the top of the stake. They were built to hold wire fencing, but also will hold up hollow peace poles. I have half a dozen peace poles in my yard in order to study them as they age. All have been slid over the top of these stakes.
This will work for stainless steel peace poles, rustable steel poles, copper poles, resin poles or any peace poles that are hollow (wooden poles are not hollow).
For rustable steel (saying the correct term "mild" steel confuses many people) this might be the best way to install them if you are going to let them rust. The first thing that will rust is the steel at ground level where is wet the most. If stakes are holding it up, it will continue to be viable in spite of that rust.
Larger Peace Poles
For a four-sided pole use two stakes in opposite corners. For any other number of sides use three.
Make a mark on the ground by setting the peace pole on the spot and then dragging something like a nail around it to mark its outline. Then drive the fence posts into the ground immediately inside that outline. On the stakes there usually are hooks that are used for securing wire fencing. Point those toward the middle of the circle so that the pole does not get hung up on them. Lean them out away from each other slightly (depending on how springy they are - thicker stakes don't spring much) so that they push against the insides of the peace pole as in the photo at right. This will necessitate either having someone pull them toward each other in order to get them all inside the pole at the beginning of the sliding, or temporarily tying them together. Be sure to untie it before sliding the pole all the way down.
Holding up a peace pole with stakes is easy and always has worked for me, but I guess I should include a disclaimer saying that I'm not guaranteeing that no one will steal it or no wind will blow it away. Where I live sustained 65 mph winds blew down two trees, one immediately next to one of these peace poles, and none of my peace poles moved, but your experience could be different.
Also, "call before you dig" applies to driving stakes into the ground. If you don't know where your underground utilities are make the call. It's free.
Once when I was putting in a fence I drove a metal stake into a 200 amp line. Sparks flew. I am okay because I was wearing leather gloves and rubber shoes and standing on dry ground. But the line had to be dug up and repaired.