I just bought this stuff from my local big box store.  It's tough and the bottom scalloped edge is sharp.  Just stick it in the ground and hammer it in.  Easiest landscape edging I've ever installed, but the price here is a little high... I got it for about $5 a section and of course no shipping!  The parts that you lock together don't really work that well and one broke off while I was hammering.  But it's in a spot that I don't really care about thankfully!