We get the drain plug washers from the local honda dealer in bags of 50 for the oil plug. I dont like how the aftermarket gaskets fit, they are a bit too big ID for my liking compared to the Honda washers. I think they are somewhere around 50 cents each, 94109-14000. That trans plug gasket is a copper gasket, the factory gasket is aluminum. We keep a few different sizes of them in stock in Genuine Honda. not real expensive.