H-Man. If you wanted to go with the minimun, you could make it with around 360 kb. With the packet saver, you could go 30 % less. That is if your provider is rock solid. There are not too many providers like that.
The exception will be if you have leased sat. bandwith.Some places that is the only option, but is very expensive.
Do not confuse leased sat. with broadband sat. like direcway.
And Joel is right. You must have Quintum and packet saver on both ends for it to work.