How about a grand final?

If you're asking Penrith, the answer is believed to be about $10 million.

And if the money is spent on the best duo in rugby league?

That's the jackpot.

When Ivan Cleary signed with the Panthers at the end of 2018 on a five-year deal, critics blasted the move as deceitful - a waste of money by a club desperate to keep their star halfback.

The coach was still contracted to the Wests Tigers.

A month earlier, Nathan had agreed to a four-year extension with the Panthers, fulfilling a dream to be coached by his dad.

All in all, the cost of Ivan's return, severing ties with coach Anthony Griffin and locking up Nathan is believed to have cost Penrith a tidy $10 million.

All on the bet that the coach they had sacked for appearing "tired" three years prior was the right man for the future.

To Penrith, he was the missing piece of the puzzle after pouring millions into their junior development system for the best part of a decade.

"The only people who thought it was a gamble was the press," Panthers boss Brian Fletcher said.

"The board never thought it was a gamble otherwise they wouldn't have done it.

"They knew it was a good investment.

"It was a good idea to get him back ... We're over all that (stuff from 2015)."

It may not have looked it last season, but Penrith's 2020 campaign has qualified the spend.

In the space of 12 months the Panthers have gone from also-rans to grand finalists based on a 17-game winning streak and the most exciting brand of football in the NRL.

While Cleary had help from assistants Cameron Ciraldo and Trent Barrett, he first needed the humility to try again.

Walking back into a place that turfed him out takes gall.

"I think the fact that he continued to live in the area and his kids continued to go to school at Penrith, Nathan continued to play here. So his life was at Penrith," club legend and board member Greg Alexander said on why Cleary returned.

The words will sting Tigers fans who feel betrayed that Cleary turned his back on a commitment to them.

But before Sunday's grand final it's a euphonious tune for Panthers fans.

"I have heard Ivan talk about his love for the Penrith area and the fact he feels like a Penrith person," Alexander said.

"He says 'I belong in Penrith'.

"It doesn't matter how you look at it.

"Anyone who gets relieved from a position would love to have another crack and prove to everyone he was up to the job."

On Monday night, Cleary collected his coach of the year award exactly five years after Penrith sacked him under those "tired" suspicions and appointed Griffin.

It was a nod from the rugby league gods that something has gone right.

The 2019 season was tough for father and son, and at times that $10 million investment appeared to weigh them both down.

First came a six-game losing streak followed by seven wins in a row.

It was the opposite of what has got them to the decider on Sunday - inconsistency.

And after the Panthers finished 10th, many thought the gamble did not pay off.

Cleary himself doubted it.

But all he needed was time and belief.

"It was definitely challenging last year and you do question yourself sometimes, it was pretty obvious at the end of last year the direction we needed to take," Cleary said.

"As I've said before, some of it is just keeping pushing with what you believe to start with and it just takes some time to get some traction.

"I'm just lucky that we've got good staff, good players and good chemistry and if you've got that you're doing OK."

And money, well, it can't buy that.

Australian Associated Press