The family issued a statement at Friday's press conference, highlighting their belief that the 20-year-old is still alive after having gone missing April 1.
The FBI's $5,000 reward was also discussed at the conference and officials say the family has already added to that amount.
"We ask that you donate whatever possible so that we can bring Aly home safe!" wrote family member Melanie Yeoman, who organized the GoFundMe page.
Alycia Yeoman was last seen Mar. 30 at her friend Mike Lizarraga's house in Yuba City.
Investigators have been combing through that residence as well as an orchard in Live Oak where her empty truck and cellphone were discovered Monday.
The GoFundMe campaign had raised $4,600 within 19 hours of its creation.