• sponsored posts are usually drop shippers
• free returns are usually drop shippers
• check reviews and search for amazon or usps or post office to see if anyone mentions how they ship
• be wary of sellers with tens of thousands of feedback

If you get drop shipped, report a problem say it’s damaged or whatever, and don’t let them send you the Amazon return - use the eBay generated label. Then they have to pay for it and returns absolutely destroy drop shippers. Then leave feedback saying they just drop ship from Amazon