I've bought off of AliExpress which is more like E-Bay. They specify shipping up front, you pay it, and your package comes.

Alibaba often involves some negotiation between the buyer and seller.

I have bought small bike parts through AliExpress, and perhaps through Alibaba with good success and direct shipments via usps, ups, fedex, or DHL.

I have bought a couple of things that were shipped freight to me which was more of a hassle. I got some tiles shipped to me. I had to pick them up at the freight warehouse. I was charged several additional undisclosed fees including a freight inspection fee and a freight dock pickup fee. And, I hadn't even been aware the shipment was coming direct to me from overseas.

A used engine also required me to get a customs waver (but customs were either cheap or waived).