Your container should at least be 64 fl oz, but a gallon container is even better. Make sure not to use a wine bottle, as that will be too small!
Many people use our glass gallon jugs as a vessel to make their wine in, but if you don't have one, you can also use a 99 cent water gallon jug from the grocery store. They work great!
You can also use a cooler or a container with a drink dispenser. Or, if you want to make a bigger batch, you can use a fermentation bucket. Since it's got some extra space in it, you won't have to pour out any wine to make space for headroom!
If you have a really big 3 or 5 gallon container hanging around, you can use that too. The extra airspace at the top isn’t a problem at all, even if you only have one gallon of wine.