A steady stream of supporters were seen entering the Tynecastle ticket office for most of the day.
Administrators BDO had warned that they needed to sell an extra 3,000 season tickets to help keep the club alive without a "fire sale" of players.
Jambos fans have been challenged to hit their target within the next 14 days if they are to plug an immediate funding gap of up to £750,000.
The club, who are £25million in debt, wrote on their official Twitter account this evening: "Ticket Centre reports 500 STs sold in 24 hours! What an effort! Keep going folks."
Fans on the Jambos Kickback supporters' website also raised £13,000 through donations on Friday.
Kenny Hogg from Bonnyrigg, Midlothian, was one of the fans who acted after joint-administrators Trevor Birch and Bryan Jackson made it clear the club would not survive without the help of the Hearts faithful.
He said: "I had a ticket last season but was swaying on whether or not to renew this season. I wasn't too keen on the regime in charge and was getting fed up with them.
"But the statement from the administrators convinced me to come down and renew. In fact, three of my friends made the same decision so I'm paying all four of us up.
"I'm still optimistic that we have got a good chance of survival but I thought I should do my bit. I'd feel guilty if I didn't."