Joshua, 27, will reportedly earn £2m for the second defence of the belt.
A proposed match against Wladimir Klitschko, pencilled in for next April, could earn the Briton as much as £15m.
"Fighters can lose their way after tasting a bit of success but it's not about money, it's about class," said Joshua, who is undefeated in 17 fights.
"It's about morals, how you conduct yourself. Glitz and glamour doesn't come into it. I don't live in luxury, I'm still at home with my mum."
Joshua often shares a gym in Sheffield with Great Britain's amateurs, with whom he shares trainer Rob McCracken.
And Joshua, who came through the same system before winning a gold medal at the 2012 Olympics, says training with young, ambitious boxers keeps him grounded.
"These amateurs who train day in, day out and live the life are better than half the pros who are taking the glory," said Joshua, who stays in the same accommodation in Sheffield as when he was in the GB squad.
"It's good to be around that, they don't give me a chance to slack."
Joshua expects to make Molina his 18th victim inside the distance, but is not complacent before the fight at the Manchester Arena.
"People like Molina are unpredictable," he said. "They seem nice but when they come in the ring they come with bad intentions.
"There is a lot of expectation on me, but it's also my expectation to win, win, win. We're singing from the same hymn sheet.
"At the moment it's going well, but there will be bumps along the way. I'd be silly not to think that, so I have to plan for things going wrong."
Molina, 34, lost his first fight as a pro in 2007 but has been beaten only twice in 27 bouts since.
In 2012 he was knocked out in the first round by Chris Arreola, before lasting nine rounds with WBC champion Deontay Wilder. In his most recent fight, in April, Molina caused an upset by beating Tomasz Adamek in Poland.
And the Texan believes he will shock British fans with a knockout victory, just as his mentor Oliver McCall did to Lennox Lewis in London in 1994.
"I have a lot of respect for Anthony Joshua, he's bringing a lot of excitement to the heavyweight division," said Molina.
"But we've yet to see him in a lot of situations. There's more to heavyweight boxing than just beating down the guy in front of you.
"There are other avenues. We're going to try to put him in some spots and surprise him.
"He thinks it's going to be an easy night, the whole world thinks it's going to be an easy night, so my most powerful weapon is the element of surprise."
Starts 17:30 GMT - times subject to late changes
4x3 mins welterweight contest
CONOR BENN (10st 7lbs 3oz)  v STEVE BACKHOUSE (10st 3lbs 9oz)
Followed by 8x3 mins heavyweight contest
LUIZ ORTIZ (17st 3lbs 3oz) v DAVID ALLEN (18st 6lbs 9oz)
Followed by 12x3 mins British light-heavyweight championship
HOSEA BURTON (12st 6lbs 5oz) v FRANK BUGLIONI
Followed by 12x3 mins British super-middleweight championship
CALLUM SMITH (11st 13lbs 7oz) v LUKE BLACKLEDGE (11st 12lbs 9oz)
Followed by 12x3 mins vacant WBA super-flyweight championship
LUIS CONCEPCION (8st 5lbs 7oz*) v KAL YAFAI (8st 2lbs 7oz)
*Concepcion failed the weight, scaled 8st 5lbs 4oz second time - title on the line for Yafai only
Followed by 12x3 mins vacant WBA international featherweight championship
SCOTT QUIGG (8st 13lbs 7oz) v JOSE CAYETANO (9st 1lbs 5oz*)
*Cayetano failed the weight, scaled 9st second time - title on the line for both fighters
Followed by 12x3 mins WBC world heavyweight title eliminator & WBC international championship.
DILLIAN WHYTE (17st 8lbs 5oz)   v DERECK CHISORA (17st 12lbs 6oz)
Followed by 12x3 mins IBF world heavyweight championship
ANTHONY JOSHUA (17st 11lbs 1oz) v ERIC MOLINA (16st 13lbs 8oz)
Live float - not before 20:00 GMT
6x2 mins super-featherweight contest
KATIE TAYLOR (9st 6lbs 2oz) v VIVIANE OBENAUF (9st 5lbs 9oz)
Anthony Joshua is adamant fame and fortune will not spoil him as he prepares to defend his IBF heavyweight title against Eric Molina on Saturday.