Simms spoke on the BBC's Super League Show before Sunday's big relegation clash with Wakefield.
"We have too many people depending on the club for their livelihood so there's no way we'll spend too much to try and survive," said Simms.
"It wouldn't be fair on the staff, the players or the supporters."
The Australian, who formerly coached Halifax, added: "We will do everything we can to stay up, and to do that, we would like to bring in new players, particularly since the retirement of Michael Hancock.
"But it takes money to get them. At this point when the club is struggling, we need the supporters to come along and pay their hard-earned cash at the gate."
Salford received a huge boost with their victory away at Widnes last weekend, and Simms sees Sunday's game as their Grand Final.
"Our new coach, Karl Harrison, has been with us a few weeks now, and it always takes a little time to get the players to play the way a new coach wants them to.
Big month
"I'm convinced he's doing a great job and that we will slowly move up the table to a more comfortable position. The players are definitely responding to him.
"We always realised at the beginning of the month that this was a big month for the club.
"Beginning with last weekend's win, we are confident that we are strong enough to stay up. Also players want to come to the club now that Karl Harrison is at the Willows."
With Salford and Wakefield both stranded at the bottom of the table with six points, Sunday's game could prove the difference between relegation and Super League survival come the end of the season.