She will face the winner of the Republican primary a contest that includes former state Rep. Chris Herrod, who won a special GOP convention Saturday, and Provo Mayor John Curtis and investment adviser Tanner Ainge, who both qualified for the ballot by collecting signatures.
"I have a two-month head start" to campaign with all voters because she has no primary, Allen said.
With $700,000 in the bank, Allen has more money than any candidate in any party. The most raised by the Democrats Chaffetz faced during his five races for Congress was $60,000.
Meanwhile, Frank had raised $5,000 and Ingwell $1,000 in the race against Allen. Both tried to attack Allen on Saturday for her large bank account.
"We are not a funded campaign. We are a principled campaign," Ingwell said.
Similarly, Frank told delegates, "Let this be a battle of ideas and not a battle of money."
Allen's fundraising benefited from controversy over Chaffetz's March 7 comment on national television that low-income Americans should prioritize spending on health care "rather than get a new iPhone."
Outraged Democrats nationally helped Allen's campaign fund grow from $20,000 to more than $400,000 in less than a week.
Of the $564,000 that Allen collected through March, 88 percent came from people who donated less than $200. For donations larger than that, about 82 percent came from people outside Utah, including a few celebrities like Nancy Sinatra.
Allen told candidates Saturday that she continues to attract support, money and interest from Democrats around the state and nation and listed possible reasons why.
"Could it be that you like me believe that government and its officials should tell the truth … believe that women should make their own health decisions … that guns do not belong in the hands of domestic abusers … [and] support immigrants who will work with us to realize the American dream?"
Although the 3rd District is overwhelmingly Republican, Allen predicts victory. "I think we have a rare opportunity. I think it's a moment in history where there is so much frustration with the Trump administration." She said her polling show residents like Trump personally, but are frustrated with his politics.
The family doctor who lives in Cottonwood Heights adds, "I want to advocate for people's health care. I think everyone deserves it. I believe it's a right. And I think I'm uniquely qualified to have that discussion. I've been in the trenches a long time."