One side includes an endorsement from former Democratic Gov. Buddy MacKay.
The other highlights Rich's experience in the Florida Senate, where she served for eight years, and stresses her progressive credentials.
"Nan has always been a leading progressive advocate for children, women, seniors and social justice issues," the mailer reads. "Her successful efforts to expand support for home and community-based care programs for seniors has allowed thousands of Florida’s frail elderly to remain in their own homes instead of moving into nursing homes."
Rich is the underdog in the Aug. 26 primary. Her opponent, former Gov. Charlie Crist, is better known and better financed.
Rich's latest mailer went out to Democratic primary voters across the state last week, campaign spokesman Sterling Clifford said.
The ad was paid for by the Florida Democratic Party. But it was neither an endorsement nor a gift, FDP spokesman Max Steele said.
Steele said the party often helps candidates get lower rates on mailers and TV ads.
"It's something we offer to both candidates," he said.
To get the lower rates, the ad must be endorsed by three elected officials. In this case, the elected officials were: state Sen. Oscar Braynon, D-Miami Gardens; state Sen. Darren Soto, D-Orlando; and state Rep. Amanda Murphy, D-New Port Richey.