I got a 6' x 9' area carpet cheap at Home Depot (the kind that they stand up in the center aisles every once in a while). The edges are bound so it won't fray on you and start pulling apart. I sandwiched the top edge between two narrow strips of wood bolted together that gives a solid surface to screw in some hooks. I hung if from the joists in the basement and the 9' length is just enough to have about 2' lay on the floor sloping back toward the pitcher. I put a weight on each corner to hold it in place (I used a couple of 5 gal buckets with sand). Now when she pitches, about 80% of the time, the ball falls to the sloped part of the carpet that's laying on the floor and rolls right back to her!! Pretty simple, cheap and effective.....
Go to a truck stop and purchase a rubber mud flap for a tractor trailer, already has holes in the flap to hang. They make a loud pop when the ball hits the flap, the kids like that, and it works well.