Black Rubber No Dig Landscape Edging - $5 4ft Section, Walmart Clearance YMMV B&M
Found this in the clearance area of my garden center today - normally $10 a 4ft section so half off, but by far the cheapest ive been able to buy any kind of edging like this. Brickseek showing all stores around me with inventory and priced at $5.
I talked with the garden center manager and he gave me a better deal buying by the box. They are in boxes of 6 and he marked them down to $25/box. Not sure how reproducible that is, but i bought 5 boxes.