First, shop around with glass people. I found windshields for less than half price without sacrificing quality or service. Unfortunately, I've had to replace three in my three smarts.
Second, shipping will run A LOT, as will cost of removal and reinstallation ... plus you run the risk of breakage ... then you lose everything!!!
IMHO, far better to get one from a reputable installer who will offer guarantee (I had one break within a few days of installing ... they didn't pick up a stress, and it cracked. They covered it, but likely wouldn't do so with a used unit.
Finally, there are two versions. The one with the rain sensor costs a chunk more ... sometimes triple!!