Vale set £1million aside to spend on players for next season and Bratt insists no more funds will be provided unless cash can be raised elsewhere.
So far new manager Micky Adams has seen three new arrivals at Vale Park this summer, with midfielders Tom Fraser and Doug Loft coming in from Brighton and full-back Adam Yates agreeing a move to ST6 before the new boss took charge.
Loan deals now look Adams's best chance to boost his playing ranks as Bratt told The Sentinel: "The budget has been exceeded so we
can't go any further. We have to get money from other sources.
There will be no players coming in unless players go out.
"The only way we can sign players later on is if somebody comes in and invests, we go on a cup run or we sell a player."
He added: "There are more people on contracts who have another year left on their deals. The contractual situation takes up the biggest part of the budget. Micky has the same players as last year, plus three more. Those players need to do better to enable us to go up the league."