NASHVILLE, Tenn. — Amazon aimed for Christmas in July with its much-hyped “Prime Day” sale. But some shoppers found a lump of coal instead.

The online retailer said Prime Day would offer bigger sales than those during the winter holiday shopping season. The goal was to boost $99 annual Prime loyalty program memberships during the sluggish summer months. The sale gained so much attention, other retailers, including Wal-Mart, Target, Macy’s and Best Buy, had sales of their own.

But some Amazon customers were disappointed by Prime Day. Some thought the discounts weren’t deep enough. Others didn’t like that the deals were only available for a limited time and in limited quantities. And still other Amazon customers criticized the types of products that were marked down.

By midday Wednesday, Amazon was offering a Kindle Fire marked down to $79 from $139, a GoPro camera bundle marked down from $691 to $500 and a Blu-Ray “Lord of the Rings” trilogy set marked down from $120 to $28. But there also were markdowns on more mundane household items like detergent and baby wipes, causing some shoppers to compare Prime Day to a garage sale.

“The biggest disappointment is that Prime Day seems to focus more on quantity over quality,” said Emily Wienberg, 24, from Boston, who was looking for a Bluetooth speaker or printer on sale.

Doug Messer, 21, from Westchester, New York, was disappointed in the sale too.

“I was frustrated to see that only a certain amount of users could claim each deal,” he said. “We found a TV we wanted and when we went to claim it, we were added to a wait list. Not really a deal if only a certain percentage of visitors can take advantage of it.”

The promotional day highlights the risk marketers face when they try to hype promotional deals and sales and don’t deliver.

Larry Chiagouris, marketing professor at Pace University, said if people get disillusioned with Amazon’s sales announcements they won’t trust future sales. “They haven’t damaged the trust people have in the overall Amazon brand, but they have done major damage to the credibility of sales announcements going forward,” he said. “People are going to get numb to sale announcements and they’ll no longer provide the traffic kick start they’re designed to.”

Allen Adamson, managing director of branding firm Landor Associates, agrees that customers won’t completely lose trust in the Amazon brand, but he questions the overall strategy of the sale.

“If you’re going to offer this, then you have to really do it right,” said Adamson.