Amass a bank balance of $50,000 during the game to win. This will not be easy since the Bloons will come at you non stop and towers are limited to tier 3 or less.
Money Management is a Special Mission in Bloons Tower Defense 5 Deluxe. Completing it earns 2000. In order to complete it, you either have to reach $50,000 or survive 300 rounds of Apopalypse on the track Military Base (the latter is highly unadvised). Selling towers rewards no cash, which makes the special mission harder. The player starts off with 1 free Banana Farm. All towers are limited to 3/3, except for the provided Banana Farm, which is 4/4.
It is advised to stop buying farms shortly before the first MOABs come in.
Spend your cash wisely as selling towers gives you no cash.
It is obviously easier to get $50,000 than to survive 300 rounds; even if attempting to survive the 300 rounds, it is very difficult to do so without earning $50,000 along the way.
You will not be able to purchase a temple or the Ray of Doom on this mission because tier 4 upgrades are disabled. Also, before a temple or the Ray of Doom could be afforded, the mission would be completed.