Are you sure it's plastisol?
Did they ask you how many colors in your design?
I don't know of any plastisol places that allow you to print just ONE.
It *sounds* too good to be true, but that doesn't mean it isn't true.
Generally, plastisol transfers are based on how many colors are in your design and how many you buy. There are
exceptions of course, but it doesn't sound like they are quoting you for plastisol.