When we bought our home we were faced with the challenge of landscaping an overgrown steep hill. We started with this (pictured above). This is only about 1/3 of the hill because this is all we’ve tackled so far.
we weed matted the hill with roofing leftovers for free from a local roofing company that was throwing the material out. It works well (not only because it was free) but it is heavy-duty and better quality than the stuff you get at Walmart.