There are many types of garden edging, but the cheapest is usually a simple trench dug around the perimeter of your garden. You can then line the trench with a bricks, stones, or other masonry, or you can simply use soil to fill in the trench. Another cheap option is to use landscape timber or railroad ties. Simply hammer them into the ground along the edge of your garden. This will also help to define your planting beds and keep mulch and soil from spilling over onto your lawn.

The cheapest garden edging is usually made of plastic. It's affordable, easy to install, and does a decent job of keeping grass and soil from spilling onto driveways and sidewalks. However, it can be unsightly and tends to fade over time. Another option is metal edging. It's more expensive than plastic but looks much nicer and lasts longer. Plus, it's very durable and can be used in areas with high traffic (like near a driveway). Finally, there's wood edging. This is the most expensive option but also the most beautiful. It adds a natural touch to any landscape garden installation and is very long-lasting.