This is a huge grind, and in my opinion the hardest trophy to get in the game (or at least the most time consuming). By the way, this achievement is CUMULATIVE, meaning you DO NOT have to have 1 million Fight Money at once. You're allowed to spend some and still get the trophy.
Fight Money Breakdown:
1.Story Prologue Mode -
Completing a Prologue will grant you 2000FM.
Level up 1 to 8 = 8lvls x 1000FM for 8000FM..
(2k x 22 characters) + (8k x 22 characters) = 44k + 176k = 220k
2.Survival Easy -
Completion - 2k FM.
Lvl up 8 to 12 = 4lvs @ 4k FM.
(2k x 22 characters) + (4k x 22 characters) = 44k + 88k = 132k
Completion - 3k Fm.
Lvl up 12 to 15 = 3lvls @ 3kFM.
(3k x 22 characters) + (3k x 22 characters) = 66k + 66k = 132k
4.Survival Normal -
Completion - 5k.
Lvl up15 to 19 = 4 lvls @ 4k.
(5k x 22 characters) + (4k x 22 characters) = 110k + 88k = 198k
5. Completing Story mode twice (once on Normal, again on Extra) = 80k
6. Demonstrations - Watching Character Demos grants you 500FM
22 characters * 500 FM = 11k
7. Beginner, Intermediate, and Expert Demonstration (1k FM each) = 3k
Right now, you would be up to 776k Fight Money. If you are going for the platinum, you should also complete the following as well to gain more Fight Money
8. Survival Mode Extreme
Completion = 20k
9. Winning 300 Ranked matches
300 * 50FM = 15k
Now, you should be up to 811k Fight Money. If you're going for the Platinum, you would also have to reach GOLD league (by reaching 4,000 LP), so you would gain more FM from online fights.
You can complete HARD or EXTREME Survival for 10k or 20 FM respectively to make up towards the remaining ~200k FM you need to reach 1million.
Finally, Missions have been added to SF V, requiring you to do various tasks such as replay a specific part of a character's story mode, perform 10 V-Reversals, Win 10 Ranked matches, perform a specific stage transition, etc. to earn Fight Money in a short amount of time.