I have actually thought about this and designed 1, it involved sinking a pole into a concrete base then welding baskets and using chains (also welded)
Basically after i planned it out i figured out it is much more expensive to make 1 (that is of good quality) then to just buy 1 offline and ship it to you.
Now if you just want to shoot around then you can buy portable ones at sporting goods storesbut if your building a course on your property i suggest buying some big wooden poles (square poles), throwing some paint on them and just sinking them into the ground. Paint a line that you have to hit above and the hole number.
If you do this its actually harder to hit then the chian basket so youll get even better!