Bear Basin makes a slip on model that sells for about $16-$20 (I bought mine at Sportsmans Warehouse). It has foam inserts to give different heights, so you can fit to suit. Only problem is that is is long enough to cover the rear sling swivel on the synthetic stock. I will trim mine and have my mother in law restitch the thread.
Another idea that might be worth considering is to buy one of the slip on cartridge carriers and put some moleskin from an archery shop under it to get the right fit. A friend of mine has a Benelli with a stick on pad, but he doesn't know who made it. It was on the gun when he bought it.
