The 16-year-old, whose body has never been found, sent hundreds of messages on the Oasis social networking website offering sex for cash in a bid to raise the funds.
She disappeared in July 2015 after Rodney Wayne Williams, 65, allegedly accepted the offer and agreed to pay her $500 for sex.
Williams has pleaded not guilty to murdering Tiffany after picking her up from a motel in Logan.
The teenager sent and received hundreds of Oasis messages before she went missing, prosecutor Philip McCarthy QC told the Brisbane Supreme Court on Friday.
“I need money ASAP. I need to pay my rent and phone bill,” one message shown to the jury sent by Tiffany on July 10 reads.
A profile named Shakz replies: “Centre link ain’t helping U?”
Tiffany replies “no” saying she is an orphan and her parents are dead.
Earlier in the day, the teenager offered another profile named Junior184 sex for $400 but the user replied it was “way to (sic) dear”.
To another, she says “I am looking for a “sugur (sic) daddy”.
The teenager repeatedly offers sex for cash, saying she urgently needs money to pay her bills.
Some profiles questioned her age. Others showed sympathy for her situation. But many attempted to barter the price down, with one offering to pay $50.
Another said: “Get a job”.
As the days’ pass, Tiffany’s messages becomes increasingly desperate.
In one message to Vegemitekid15, she answers “s***” when asked how she is before again offering sex for cash so she can “pay the rent”.
The court has heard the teenager was living at the $100 per night Waterford Motor Inn with her boyfriend Gregory Hill, who was unemployed.
An Oasis message log shows that on July 12, Tiffany started communicating with the profile Muddless54, who she offered sex for money.
Mr McCarthy said it was Williams.
The court heard that after the pair negotiated, Williams picked Tiffany up in his car about midday.
Williams then drove to Larapinta industrial park where “something happens”, Mr McCarthy told the court.
He then drove to the Esk-Ferndale region, where police have searched dams and bushland for Tiffany’s body, without success.
Tiffany’s Oasis messages abruptly ended on the same day at 1.26pm, he said.
Her last message simply read: “Hey”.
The court heard Tiffany had created more than a dozen user profiles on the Oasis website in the months before she disappeared.
The teenager listed her age as 21 and used profile names such as Hotsexylady1 and Sexybabe11232, often also with a photo.
Earlier, Mr Hill, 45, denied pimping the teenager out despite 300 messages about money and meeting men allegedly being found on his phone.
The trial continues.