MK Dons manager Karl Robinson says investment will be required to establish them as a competitive force in the Championship next season.
Robinson's side sealed automatic promotion to the second tier with Sunday's 5-1 home win against Yeovil, after Preston lost at Colchester.
Next season will be the club's first outside of the bottom two divisions.
"We don't want to be a number, we want to compete, but we need to spend," Robinson told BBC Three Counties Radio.
"If we want to compete, we need to spend money on the right players.
"We've got some young players, players who will grow with us and get better.
"This is the biggest day in our history, hopefully we can now go onto bigger and better things."
The Dons have made use of the loan system to bolster their promotion bid, with Chelsea midfielder Lewis Baker, Walsall striker Will Grigg and Dele Alli, sold to Spurs and loaned back, among those playing pivotal roles.
Alli, 19, scored 16 goals in 44 games and will join Tottenham for next season in a £5m deal.
"You can see what it means to the players, even the loan players who are all jumping up and down," Robinson said.
"Lewis is only here on loan, but look what it means to him.
"We wish Dele luck. He moves on now, he set his stall out at the beginning of the season to move for millions and get the club promoted and he's done that."