Buy Everything

"All premium upgrades, including Double Cash,Monkey Tycoon, Crystal Ball,Double Ranga, Explosive Darts,Frag Bombs,Digital Amplification,Dreadnaught,and Rank 31. With Rank 31 you will unlock all non-purchasable upgrads such as all tower types & all upgrades for them, all game modes such as Sandbox & Apopalypse Modes."

- Official quote from Bloons Tower Defense 4.

It costs 100 .

It has every  premium upgrade plus Rank 31.