| “ | A one-time infusion of 10,000 money so you can sock it to those bloons. You can only use the money in your current game so purchase and spend it wisely. | ” |
| ~ BTD5 description of the Cash Injection Premium Upgrade |
Cash Injection
Cash Injection is a Premium Upgrade that exists in Bloons Tower Defense 4, Bloons Tower Defense 5 and Bloons Tower Defense 5 Deluxe. It is also in BTD battles as a power. It instantly gives you 10,000 money upon purchasing it in game, and can only be used in the current game. However, Cash Injections can help you get an early edge or get out of a tight situation. You can't use this Premium in Deflation Mode. It costs 
3 in BTD4 , 5 in BTD5 and 
200 in BTD5D . This can be bought an unlimited amount of times.
Tips[]
- Use it in the early rounds, as it is almost useless in later rounds, because the player will be making more money in the higher rounds than Cash Injection gives.
Trivia[]
- If you have
50 (2000 on Deluxe) or more you can purchase enough money to get a temple of the monkey god on round one on Medium Difficulty.
- However, you will need 15 (600 on Deluxe) more if you don't have the Sun God upgrade for it in order to build its upgrade before continuing.
- However, you will need
- Strangely, one can buy a Cash Injection in Sandbox Mode, although it won't have any effect.