DIY - Homemade Gabion wall ie rocks encased in wire baskets and used as a retaining wall - creates a dramatic feature in a garden. No directions on link. Nice someone figured out how to landscape with river rock. I swear they grow!
How to build a cheap garden rock wall or a simple concrete reinforced retaining wall. If you do not have much money and can't easily fix stuff you probably can still build these simple retaining walls.