I use a 6 litre transparent 'storage box' from Canadian Tire or the Dollar Store that I bought for $1.50. Neither of my cars hold more than 4.5L, so as long as I don't kick it, it works just fine. Square corners make for easy pouring into the funnel for the waste jug.
I also have one of the big pancake pans with the spout, but always found them cumbersome and the spout took forever to stop dripping, so I have not used it in close to a decade.