Bollards in a commercial application are a steel tube filled with concrete. Depending on where you are you can buy them empty or prefilled from suppliers.
The bollard will need to be embedded in the ground 18" minimum, and more is better.
Also note there are bollard covers of either painted steel, stainless, or PVC. Makes an ugly steel pipe sticking our of the ground more attractive.
We have a huge, cube-shaped boulder on our property that we use as a horse mounting aid. Bought it from a landscaper, they delivered/placed it.
A horse mounting aid? Ya know, sheep are a more compatible height for that pervy stuff and I bet they don’t kick nearly as hard when you surprise 'em that wy.
Not seeing your lot or the entry to your driveway…
Purchase an 8’ piece of 4" diameter PVC. Cut it into thirds.
Purchase caps for the PVC pipe. Three of them.
Purchase one or two bags of sand (maybe a bag of concrete)
Dig hole about a foot deep. About one foot wide.
Drop PVC pipe into hole. Make a triangle of the three pieces.
Fill PVC with sand/dry concrete. Put rest of concrete in the previously mentioned 1 foot deep hole.
Put caps on PVC pipe. Water hole.
Paint it whatever color you want so people will see it. Perhaps put some reflective tape on it (I recommend that).
Make it LOOK like you better not run into this. And this would cause damage to a car.
A days worth of work. No permits required. Maybe $60.