Here Borderstone concrete link blocks were used to create both a highly functional and contemporary looking retaining wall/garden edging.	At approximately $2.50 per block and with great ease of installation this garden edging/retaining wall option is highly achievable on the modest of budgets.
A solid concrete footing is recommended both under and behind the bottom run of blocks which is the most expensive feature of this type of edging/retaining wall. However cheaper foundations such as road base, mortar or crusher dust can be used as cheaper foundation alternatives on walls of heights not exceeding 1 meter.
	Alluminium edging is excellent for contemporary themed garden areas and is the preferred material for tight corners or small circle garden shapes. Very easy to install and extremely durable for long periods.
Using timber for garden edging is the cheapest option available both for supply and installation. Installation here is through installing steel rods through the bottom of the logs and then into the ground. Installation is very quick and this type of material is consistant with tropical and natural themed gardens.	The hardwood sleepers used in this garden situation provide both a retaining and edging purpose. For a budget option the sleepers can be held in place through hard wood timber pegs driven into the ground then attached with batten screws. However concreting hard wood posts or sleepers is recommended for longevity of the installation.	I regularly use this form of garden edging due to it's cost effectiveness in supply and installation. While this product can also be used for more gentle garden curves and is attractive looking with both a smooth wood grain side and a textured decking side. Installation is with hard wood stakes driven into the ground then fixed with batten screws.