Delivery service companies UPS and FedEx could be bigger winners from Amazon's Prime Day, CNBC's Jim Cramer said Monday.

"If it's really that great ... just play them," Cramer said on "Squawk on the Street."

Cramer spoke before Amazon's third annual Prime Day begins Monday evening. The e-commerce giant launched the discounting event on July 15, 2015, to commemorate its 20th anniversary and to advertise its $99 annual Prime loyalty program.

Amazon Prime packages are mostly shipped via UPS, according to Amazon's website. But in areas not served by UPS, FedEx is used as an alternative.

Regarding the broader stock market, Cramer said investors should close pay attention the Federal Reserve this week, including Chair Janet Yellen who is scheduled to testify in front of Congress on Wednesday and Thursday.

"We need to hear every Fed and their talking endlessly. ... Officials say we're going from three hikes to four based on the employment number on Friday," Cramer said. "Three hikes to four hikes means you can go into these bank quarters, which are reported on Friday, with a full head of steam."

On politics, Cramer said Congress has too much time on its hands and it doesn't need to take an August recess. He said he is concerned whether the Trump administration can get tax reform through this year with the health-care roadblocks.

Sen. Pat Toomey, R.-Pa., said a new version of the Republican health-care bill is expected on Monday, and he hopes it can appeal to both sides of the party's divide.

"I'm a little discouraged," Cramer said about tax reform.