More than 3,000 donations - from Dollars 5 to USD 250 - have rolled in since November 6, when the GoFundMe campaign was set up on behalf of Juli Briskman.
Three days later, the 50-year-old marketing executive was sacked by her company, government contractor Akima.
Now a GoFundMe campaign has been set up in Briskman's honor, describing her as an "inspiration". It has since raised more than $57,000 (£44,000) and says it aims to raise a total of $100,000 (£76,000). "You can show your support by donating here".
Briskman, 50, was riding her bike near her home in Sterling, Virginia on October 28 when the president's motorcade passed, having just left Trump National Golf Club.
"But they told me I violated the code of conduct policy", Briskman said to media.
She gave President Trump's motorcade the finger - and now supporters are raising tens of thousands of dollars for her.
Despite losing her job, Ms Briskman said she did not regret the incident, adding "I'd do it again", and has since made the photo her profile and background picture on social media.
The US president was making his 96th visit to one of his properties when Briskman saw red and flipped him the finger.
Briskman, a Democrat, worked in marketing and communications for the company for about six months.
"He was passing by and my blood just started to boil", she said.
Briskman has thanked online donors, writing "Through your very generous donations, many of those heavy burdens have been lifted".
Juli Briskman, an accomplished flipper of birds, is getting the support she deserves after getting canned from her job.