Amazon's annual Prime Day sales are here again. The e-commerce giant is making the now-misnamed Prime Day a four-day event for the first time. Its promised blitz of summer deals for Prime members started at 3:01 a.m. Eastern time on Tuesday and runs until early Friday. The company launched the event in 2015 and expanded it to two days in 2019. Amazon executives declined to comment on the potential impact of President Donald Trump's tariffs on Prime Day deals. Some retail analysts expect U.S. consumers to make purchases this week out of fear that high taxes on foreign imports will make items they want more expensive later.

It's one of the most under-publicized policies of some of the biggest U.S. retailers: sometimes they give customers full refunds and let them keep unwanted items too. Returnless refunds are a tool that more retailers are using to keep online shoppers happy and to reduce shipping fees, processing time and other ballooning from mountains of returned products. Companies such as Amazon, Walmart and Target have decided some items are not worth the cost or hassle of getting back. Think a $20 T-shirt that might cost $30 in shipping and handling to recover. While the practice is not exactly a trade secret, the way it works is shrouded in mystery.