I double seal my bags manually, just by doing it twice. I do get some of the bags loose seal, but it's usually from a roll and usually with Ribs: Espec. Baby backs. Once in a while, you'll have a sharp bone somewhere that pokes a hole in the bag. I use food saver bags, which adv. about 22-25 cents a foot, as I bought them in bulk with coupon codes and such.
One day, I’ll get a better one, but have to use up all these bags first.