By midday $22,400 had been donated by 300 people. Donations ranged from $5 to $500.
Sophie's family can also seek financial support from ACC, a spokeswoman confirmed.
"The types of financial support ACC may be able to provide include a Funeral grant of $5,788.92 to help with funeral and/or memorial costs. This can also be used towards repatriation expenses," she said.
Other grants may also be available.
Alongside donations people left messages of support and tributes on the page.
"I'm so sorry to hear Laura. Sophie was an amazing girl, so bubbly and warm hearted. Fly high Sophie, and rest in peace with your mum," wrote Sarsha.
Another donator named Sally wrote: "losing a twin is like losing half oneself".
"Really sad to hear about Sophie and I'm sure it's going to be hard Laura as she gave you so much to remember. Not today, or tomorrow, but in time things will be alright," said Jeremy Merwood.
A friend, Christopher Harper, said Sophie touched a lot of lives.
"She was a fun-loving, bubbly girl. She was just a really neat girl and not often you can truly say someone was so genuinely hearted ... She was a lot of fun."
Mr Harper, who set up the fundraising page with Mr Thomas' brother Christopher, said there were few avenues available to accumulate funds for a funeral for Sophie.
He said the only immediate family member left was Laura.
"So rather than just leaving it on Laura's back, a lot of friends have rallied around and thought it was a good idea to get a Givealittle page."
It is understood the twins' parents are no longer alive.
A friend of Sophie said there was "a very strong support network" rallying around Laura, Simon and their family.
"Our focus is primarily with Laura, Simon and honouring Sophie's life in a manner in which such a special girl deserves.
"The support from both the general public and people who knew Sophie has been truly overwhelming. Kind words and donations to the Givealittle appeal have been greatly received and will help both now and in times to come for the people most impacted by this tragedy."
Another friend, Zach Du Burgess, described Sophie as a "magnet of happiness". "She is survived by all of us but she is also survived by her comments and her character and her good nature. We love her to pieces."
He said news of her death was "crippling".
"We've lost one of our very close friends, we're a family and she doesn't have family.
"Her dad passed away ... before she got to meet him, her mum died ... and her and her twin are the last ones left and we are her family, and we're here to do whatever we need to do."
According to a police media statement, the couple's car collided with another on State Highway 1 when one attempted to turn right into a driveway.
Last night, Mr Thomas, who was driving the car, was still in hospital recovering from injuries.
Sophie and Laura featured in the 2012 television show Missing Pieces in a bid to track down their father, who had left their mother before they were born. Their father had actually died eight years earlier but the girls instead discovered they had an older half-sister, Nicky Sikora.
The half-sisters have since grown close; the day before she died, Sophie posted a picture of herself with Ms Sikora on social media saying, "Love my sister, such a beautiful soul".
Sophie is believed to have been travelling home from the funeral of Ms Sikora's mother when the crash happened.